Made one of these for my 20' enclosed cause I was tired of using the top mounted crank handle. It is made from 416 stainless steel and has all stainless hardware. Hex size is 3/4, thru bolt is 1/4" and hole size is 1/2". All you need to do is remove the existing top mounted crank handle, replace with this and use a cordless drill with a 3/4 socket to adjust the front jack foot height. Some crank thru bolts are slightly smaller than 1/4"(metric) and will have to be enlarged to use the included S.S. hardware...or you can use your existing bolt and nut.
I did a short run of these and now have them available for sale for 20 bucks with free shipping to continental U.S.
Send me a PM if interested, or send $20.00 via PayPal with shipping address to ejkorecky@yahoo.com
ej