Thought I'd post my own experience. Go to liftsupportdepot.com and they have all brands and sizes. I have a 128lb RTT & 100lb rack/frame on my custom trailer rack. 5ft at the lower "transport" position, and then lifts up to 6.5ft for opening the RTT and using the Annex. Yes, I had to buy a few pairs of struts (force vs lengths) before I "dialed-in" the right lifting capacity and strut locations. But at only $20-40 a set, it was not that bad. and MUCH cheaper than electric. (my opinion) It was not obvious to know how much lift is needed versus being able to lower the RTT back down easily. I ended up using two 60 lb Suspa struts. I now have about 20-30lbs of "net vertical weight" on the RTT and frame due to the complex lifting angles and the way my lift frame is designed. Very easy to get the lifting started with one person. And still enough weight to allow the RTT to come back down slowly, and stay down on the highway.