Abstract: A protective encasement for a vehicular trailer coupler of the latching lever towball and tongue type, completely covering the top land sides of the coupler. The encasement is made of strong thick-walled material such as but not limited to thermoplastic alloy molding and is secured to the coupler by a removable customized internal shackle through the latch lever lockhole. The shackle ends are locked into a completely encapsulated lockbody. When locked, the encasement outer wall is continuous except for the recessed lock keyhole and the flush shackle grip. This encasement provides protection for attached and unattached trailers, strongly resists tampering, is impervious to the weather, protects individuals against injuries from protrusions on the coupler, safeguards the trailer from accidental uncoupling, can be produced in bright external colors for highly visible identification, and requires no coupler or vehicle modification.