An inertial igniter including: a body having a base and three or more posts, each post having a hole; a locking ball corresponding to each post, wherein a portion of the locking balls are disposed in the hole; a striker mass movably disposed relative to the posts and having a surface corresponding to the posts, the striker mass further having a concave portion corresponding to the locking balls, wherein a second portion of each locking ball is disposed in a corresponding concave portion for retaining the striker mass relative to the posts; a collar movable relative to the posts; and a biasing element for biasing the collar in a first position which retains the striker mass, the biasing element permitting movement of the collar to a second position to release the striker mass relative to the posts upon a predetermined acceleration profile.