Do you hate switching between the jack pump and relief valve with the handle?  Do you wish there was a fly ass knob you could turn to keep your dainty hands soft? Well, this is for you!
 
Polyurethane press on knob for Harbor Freight Jacks. 
Works on all Harbor Freight manual jacks, for example the 20 Ton Press and Cherry Picker/Engine Hoist.
May fit other brand jacks. 
 
If you want one for your machine and this doesn't fit, reach out to me and with a few dimensions, I can get one made and shipped in about a week!