The 3M™ Secure Click™ Speaking Diaphragm Assembly is a replacement part for 3M™ Secure Click™ HF-800 Series Half Facepiece Reusable Respirators. Easy to install, this speaking diaphragm is designed to help provide easier communication while you work. If the speaking diaphragm on your 3M™ Secure Click™ HF-800 Series Half Facepiece Reusable Respirator with Speaking Diaphragm is damaged or worn, reach for this replacement part.The 3M Secure Click Speaking Diaphragm Assembly can be used on the following models: 3M Secure Click Half Facepiece Reusable Respirator HF-801SD, 3M Secure Click Half Facepiece Reusable Respirator HF-802SD, and 3M Secure Click Half Facepiece Reusable Respirator HF-803SD. Each unit is sold separately.