Big Red 5/8 in. Dia Trailer Hitch Receiver Lock Pin with Keys (2-Pack) ATRMT8026R - The Home Depot
Amazon.com: Kohree 5/8 inch Trailer Hitch Locking Pin, Solid Harden Steel Tow Receiver Hitch Lock with Extra Safety Clip & Anti Rattle O-Rings Fits Class III IV V 2 inches and 2-1/2
Zone Tech Trailer Hitch Receiver Lock Anti-theft 5/8" Pin For Class Iii Iv 2" & 2-1/2" Receiver With Rubber Cap - Receiver-for Tow Trailer, Car, Boat : Target