Coupling unit & Coupling head
Coupling heads and coupling units, sometimes also called overrun devices are all vital accessories when it commes to attaching the trailer onto your vehicle in a safe manner. At our online store, you will find plenty of coupling heads and coupling units, which have been produced by renowned manufacturers such as AL-KO, KNOTT, WINTERHOFF and STEELPRESS. The accessories in question boast a GVW values ranging between 700 and 3500 and are available at very affordable prices. If you want to travel risk-free with your trailer, simply get your hands on a coupling unit today and save yourself from all the hassle.

Coupling heads
Coupling heads are used to attach the trailer onto a vehicle. There are many different types of coupling heads - coupling heads for V-shaped drawbars, coupling heads for T-shaped drawbars, coupling heads for pipe-shaped drawbars etc. The main point of difference between them however, is their maximum permissible GVW value, maximum load capacity of the coupling hook and last but not least, their spacing between mounting holes, which can all vary from model to model. In the case of coupling heads available in our online store, all the information that you need for individual coupling models can be found on the product's page.Coupling heads are equipped with a wear indicator, which helps to assess when the accessory in questions needs replacing. Another helpful source of information about the coupling head is the coupling correctness indicator, with the aid of which trailer users assess whether or not the trailer has been correctly connected onto a vehicle.
Trailer coupling units
Trailer coupling units also known as overrun devices are trailer accessories which are made up of not only a braking system but also of a coupling head and a steel casing, which connects the device together. It is possible to replace individual coupling unit parts rather than then whole set. It is also possible to equip the unit with shock absorbers.Coupling units for heavy-duty braked trailers with a GVW of 750kg or more are mounted onto drawbars of regular car trailers and tow trucks. There is no need to assemble a coupling unit onto a light-duty trailer, as it is required neither by law nor by sheer laws of physics, which would otherwise demand for a heavy-duty trailer to be equipped with such an accessory. Using a coupling unit will therefore increase safety levels when your trailer is in drive mode and will thus significantly decrease the force exerted on your car's brake system.
Car trailer coupling heads and coupling units
The more a car trailer coupling unit is used, the more likely it is that it is going to fall victim of natural wear and tear. Before you head off on a long trip, it is worth checking the wear indicator of the coupling unit and the coupling head.Coupling units are the only trailer element apart from the brake cord which connect the trailer with the towing vehicle. Assemblying the trailer coupling unit correctly is the first step which needs to be taken in order to reassure oneself of a safe drive. Here, at Unitrailer, we care about high quality products. It is for this reason that we sell only AL-KO, KNOTT, WINTERHOFF and STEELPRESS coupling units, as they offer the highest possible quality on the market. Choose the right coupling unit today and take care of your brake system the right way!

Ball coupling for trailers WW 8-Y Winterhoff

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Coupling head Winterhoff WW 8-D40 800 kg 40x40 mm

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Coupling unit for trailers - KNOTT KF27 2700kg

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Coupling head for trailers AL-KO AK7 750 kg 60 mm

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Trailer coupling hitch 750 C for pipes with a 50 mm diameter


Bellow for overrun device AL-KO 161S/251S/251G FI50

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Coupling head for trailers Knott K 7,5-D 60 mm 750 kg

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Safety rubber bellow AL-KO 30S/60S/90S FI35

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Coupling head for trailers Steelpress ZSK 750 H


Coupling head Winterhoff WW 8-H 800 kg 70x70 mm

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Coupling for trailers AL-KO 3000kg V 251G AK301

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Rubber bellows - KNOTT KF27-KF35 safety rubber


Overrun device for trailers AL-KO 251S 2700kg

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Cast-iron ball coupling AK301 3000kg fi 50 mm


Ball hitch for trailer Knott K14A fi 50 mm N-3

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Shock absorber for overrun device AL-KO 251S 2700 kg - new model

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Coupling head for trailers Winterhoff WW 8 - GVW 800 kg

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Overrun coupling damper KNOTT KF27A 1600-2700 kg

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Support bracket for overrun device AL-KO 150 mm

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Coupling head Winterhoff WW 8-C 800 kg

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Coupling head AL-KO AK270 2700 kg ∅ 50 mm


Cover for trailer overrun device

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Overrun device AL-KO 60S/2 750kg

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Coupling head for trailers Steelpress ZSK 750 J 70x70 mm

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Coupling unit for trailers - KNOTT KF17 1700kg

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Coupling unit for trailers AL-KO 3500kg V 2,8VB1 AK351

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Trailer bellow - rubber protection for KNOTT overrun device KFG35


Overrun device bellow AL-KO 2.8VB FI60

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Overrun device lever AL-KO 161S 251S 251G


Coupling unit for trailers AL-KO 251S 2700kg + AKS3004

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Universal KNOTT overrun device cover

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KNOTT overrun damper for KF27B 2700 kg


Friction pads AL-KO AKS3004

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Trailer overrun damper 161S 1600 kg - new model

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Coupling unit for trailers KNOTT KFG35D 3500kg

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Coupling head AL-KO AK351 3500kg for 251S

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Coupling unit for trailers AL-KO 1600kg KW100 161S AK160

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Tie rod for overrun device model KF13, KF17, KF20 by KNOTT

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Hitch damper for KNOTT KFG30 2700-3500 kg

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AL-KO AKS 3504 hitch with anti-theft protection


Front and rear friction pads AL-KO AKS 3004/3504


KNOTT trailer tow ball coupling KS30 3000 kg fi 35/40/45/50 mm

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KNOTT overrun absorber for KF7,5 750 kg


AL-KO overrun brake damper 2.8 VB/1 PROFI 3500 kg

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Zaczep kulowy Winterhoff WW 8-B 800 kg 60 mm

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Coupling unit for trailers AL-KO 3500kg KW120 2,8VB1 AK351

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Overrun brake damper 351VB 3500 kg

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AL-KO overrun damper 2.8 VB/1 3500 kg

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Overrun shock absorber 251S 2600 kg - old model

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Stabiliser coupling AL-KO AKS 3004 - up to 3000 kg


AL-KO DIN drawbar eye DIN 2,8VB 351VB ⌀ 60

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KNOTT KFG30 3000 kg coupling unit for trailers

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Tow hitch with stabiliser KNOTT KS30 3000kg fi 50 M14//M12

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KNOTT overrun damper KF9 500-1000 kg

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Overrun brake damper 251G 3000 kg

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AL-KO friction pads AKS 1300


WS 3000 D+Z Winterhoff ball hitch with stabiliser


Overrun device for trailers AL-KO 750kg KW60 60S/2 AK161

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