Talk-A-Phone Talk-A-Phone MS-400 Flush Mount Sleeve JMAC# TALK-A-PHONE-MS400 The MS-400 is a mounting sleeve box for flush mounting 100, 400, and 500 series Talkaphone emergency phones. Also known as: TF-MS400, MS400 Technical Specifications: MSRP: Was: Now: $68.00 Add to Cart