Lunar Module Restraint Equipment
Of course, the Apollo Lunar Module had no seats due to weight constraints. However, the crew couldn't just be floating around during flight operations in zero-g; some sort of restraint system was necessary.
To quote from the Apollo Operations Handbook: Lunar Module LM-6 and Subsequent: Volume 1: Subsystems Data (LMA790-3-LM 6):
The restraint assembly consists of ropes, restraint rings, and a constant-force reel system. The ropes attach to D-rings on the PGA sides, waist high. The constant-force reel control provides a downward force of approximately 30 pounds; it is locked during landing or docking operations. When the constant-force reel is locked, the ropes are free to reel in. A ratchet stop prevents paying out of the ropes and thus provides zero-g restraint. During docking maneuvers, the Commander uses pin adjustments to enable him to use the crewman optical alignment sight (COAS) at the overhead (docking) window.