The TR-657 is an easy clean holster designed for use with the TR-659 Adapter and TR-630 Battery. The holster is designed to keep the battery adapter and battery protected and secure during use.The 3M Versaflo Easy Clean Holster TR 657 is designed for use with the 3M Versaflo Battery Adapter TR 659 Adapter and 3M Versaflo Standard Battery TR 630. The holster is used to keep the battery and adapter combo protected and secure during use. This product is meant for use with 3M Belt Mounted Powered Air Purifying Respirator GVP by users that need a new power source to work with their existing systems.