Filter bags made of PTFE needle felt are also available in the following less common designs:
- antistatic
- with PTFE membrane
- with brown fibers
- with microfibers
- antistatic with PTFE membrane
The common requirements for use of material enriched in this ways are:
- explosive dusts
- very fine dusts
- requirement of very low emission
- high aggressiveness and abrasion of dusts