Rare Kavallerietasche Reichswehr gasmask filter marked R. Larsen Berlin S.W.4B, FB 41 bwz

Rare Kavallerietasche Reichswehr gasmask filter marked R. Larsen Berlin S.W.4B, FB 41 bwz. This filter and its accompanying pouch was made specifically for Kavalerie units before the M38 gasmask was introduced. The filters for the Reichswehr gasmasks are hard to find; this is the first time I've ever encountered the cavalry filter pouch with filter. The filter is in good condition but I believe there is some corrosion underneath the leather, but I chose not to remove it from its cover. This is a very rare Reichswehr era gasmask filter with pouch and belt attatchment!