Trailer Coupler Lock, Fits 2 In & 2-5/16 In, 3 Keys

Bulldog trailer coupler lock helps deter theft by covering your hitch and blocking unauthorized hookups on RV, trailer, and boat couplers. Designed to fit two common Bulldog coupler sizes (2 in and 2-5/16 in), it uses a heavy carbon-steel body with a thick wall and protective coating for dependable outdoor use. Quick to install with one hand, it includes 3 keys for everyday parking and storage.

• Fits 2 in (50.6 mm) and 2-5/16 in (58.6 mm) Bulldog couplers—verify coupler size before purchase.


• Delivers heavy-duty security with a thick-wall carbon-steel housing built to help deter prying and drilling.


• Installs in under 30 seconds—unlock, place over the coupler, and lock for fast hitch protection.


• Includes 3 keys, dust cap, and internal cushion pad for a tighter, quieter fit and smoother daily use.


• Withstands outdoor exposure with a corrosion-resistant powder-coated finish for RV, trailer, and boat storage.

Protect your trailer when it’s parked at home, at a campsite, or in a storage lot. This nesting-style coupler cover lock is built for frequent use, combining a rugged steel shell with a weather-ready coating and a dust cap that helps keep the keyway cleaner in rain and road grime. Whether you’re securing a travel trailer, utility trailer, or boat trailer, it’s a straightforward way to reduce theft opportunity and add visible deterrence. Grab yours today and lock up with confidence.

• Compatible coupler type: Bulldog coupler


• Compatible sizes: 2 in / 50.6 mm; 2-5/16 in / 58.6 mm


• Main material: Carbon steel with surface coating


• Wall thickness: 0.24 in / 6 mm


• Product weight: 11.9 lb / 5.4 kg


• Product dimensions: Φ4.53 x 8.86 in / Φ115 x 225 mm


• Internal depth: 7.09 in / 180 mm


• Internal diameter: 4.02 in / 102 mm


• Keys included: 3