BSA will service them Fat man...as you know J.B. can also "do things" to them...but they only have a very small air resovouir so you'll never get the same amount of shots as a Rapid...
But...if you get the Low fill,you can charge that up in the field from a buddy bottle,& you get about 3 fills from that..so if you start out on full charge then top up from the buddy bottle 3 times you get 150+ shots...... ATB,Chris.