Spyder 9 Round First Strike Capable Paintball Magazine AR Style Straight Magazine 9 Round First Strike or .68 Caliber Paintball Capacity .68 Caliber Soft Spring plus First Strike Spring Included (assembly required to switch springs) Guided Ball-Pusher w/ Easy Lock and Load Compatible with E-MR5, MR5, Hammer 7 to shoot First Strike and .68 Caliber Paintballs. Compatible with MRX and MRX Elite to shoot .68 Caliber Paintballs Only