https://www.amazon.com/SWAG-Machined-Thumb-Hydraulic-Bottle/dp/B07FT1NS8R
So on the jack there is a release knob you have to tighten to make the jack go up and then when you are done you turn it and the rod comes down. Normally you have to take the handle and use it like a wrench to turn the knob back and forth. it's very handy to just have a permanent knob on there you can turn by hand. people sell them on Etsy, eBay, Amazon, just 3d printed (or milled).
SWAG Off Road Machined Thumb Knob For Hydraulic Bottle Jacks https://www.amazon.com/dp/B07FT1NS8R/ref=cm_sw_r_cp_api_glt_fabc_GG6B8N7753B1B6X77TG4?_encoding=UTF8&psc=1