The Caliber ISP is one of the ISP PERFORMANCE SERIES of kits, which feature factory pre-slotted airframe and through-the-wall fin construction and high power motor capabilities, the CALIBER ISP is a light weight, high power performer. The 54mm motor mount is great for Level 1 motors. An Aerotech J-90 motor puts this kit out of sight – try one out if your field can handle it. It is a very cool flight! (and sometimes a long walk) This kit flies great on a variety of G , H and I motors using the optional MMA-3 (for 29mm motors) or MMA-4 (for 38mm motors) motor mount adapter. Includes baffle system.