Up for your consideration is ONE SCUBAPRO "NEW" 11.150.102-P MIXING CHAMBER ONLY for 'S" POPPET used with balanced and adjustable SCUBAPRO Regulators. R-109, R-156, G-200, G-200-B, G 250, G250-HP, G250V and others. These are upgrade balance chambers but, the older versions work okay with the new poppet. The Upgraded New version is on the left in photo. Item Number:11-150-102PIf you have any questions or in need of more photos please write me and I shall get back asap.