This is a Mega Bloks ProBuilder Sea Wolf Submarine building set, model number 9775. The set contains 2,450 pieces and is designed for ages 7 and up. It features lights, sounds, and action, requiring 3 AA batteries (4.5V, not included).
The box and contents show wear, and interior parts are stored in separate zip bags, which may indicate that the contents are not fully sealed or complete—buyer should verify completeness before bidding. The set replicates an Ohio 558N class submarine, with interior play features and detailed compartments. Originally released in 2001 by Ritvik Holdings Inc. See photos for measurements, if taken.