A time-depth integrator for divers to indicate when a diver is approaching or has reached the maximum safe time limit for a dive without requiring decompression procedures when surfacing includes an evacuated chamber with an elongate channel communicating therewith. The channel has a breakable seal and contains an orifice so that when the seal is broken under water, water flows through the orifice into and along the channel to the evacuated chamber. Indications along the length of the channel show how far water has progressed in the channel and indicate the maximum safe limit and approach thereto.

A ski stop is associated with a heel tightener for safety ski bindings that comprises a boot heel-supporting turntable to which there are pivotably secured two pull members, one passing each side of the boot heel, which carry a sole retainer movable against the force of at least one spring. To permit stepping into the binding without prior manipulation and automatically bring the ski stop to a position ready for operation, a base plate fixed to the ski and carrying the turntable has a horizontal cross-shaft to which there is pivoted a pedal of the ski stop that is pivotable against the force of at least one spring to a position above the turntable at least approximately parallel to the base plate. At least one lever in the form of a braking skid is hinged to the pedal parallel to its pivotal shaft and the arm of the lever is guided for longitudinal movement in an eyelet on the ski.