Don, I got this from AP Racing site.
Safety
NOTES ON SAFETY, INSTALLATION & USE.
AP Racing Air Jacks are designed to operate at a maximum pressure of 20 Bars. Never work under a vehicle supported only by Air Jacks unless safety props are fitted.
Do not use 'U' bolt type clamps as distortion of the body will cause the Air Jack to stick. Do not loosen or remove adaptor. Jacks must be vertical during operation. Mounting brackets or clamps to be fitted to threaded section of body only. Do not use petrol or paraffin for cleaning the Air Jacks as this will damage the rubber seals. Use an alcohol based cleaning fluid e.g. Methylated Spirit. Use only silicone spray or silicone grease when internal lubrication is necessary.
Ensure end cap reinforcing ring (CP2995 & CP3723 Air Jacks only) is tightened before use. Inlet connections are designed
for dash 6 hose fittings such as Aeroquip or Goodridge.
Hope this helps.
Joe B