TrapMaster Drain Camera SkidTrapMaster Drain Camera Roller Skid Drain Camera Skid TrapMaster is designed to negotiate a trap in a 4 inch pipe and keep the camera head centered during that process. Eight wheels that are connected to the centering skid help it to roll in drain lines from 4 inches to 6 inches in diameter. The skid itself is manufactured from durable composite nylon as the Universal Roller Skid and helps to protect the camera head and extend its lifetime. TrapMaster