MJG confirmed they will fit in: 1/4 A3-3T, 1/2 A3-2T, 1/2 A3-4T, A3-4T, A10-0T, A10-3T, A10-PT, 1/2 A6-2, A8-0, A8-3, A8-5, B4-2, B4-4, B6-0, B6-2, B6-4, C6-0,C6-3,C6-5 ,C6-7 --If these can fit into 1/4A, 1/2A and A3s, they'll fit in any Estes motor as those have the smallest nozzle.