Yes, at the moment they're the only size. A 40-60 size version will be available later this year but they'd be overkill for a 25 size model. The units available now are rated for models up to 4 lbs. I have a couple of these units slated for upcoming 30 size projects (a Dalotel and a Mystic) and they appear to be plenty strong.

The only catch is that they're metric. The struts and axles are 3mm which requires metric wheels or some sort of bushing in standard 1/8" axle wheels.

They are extremely cool! You won't be disappointed. Rigging up servos or pneumatics on models this size is always a bit of a chore. These units do away with all that work.

David.