3 stars because of instructions. Bought for using strong chemicals to de-mold a shower. Maybe it’s me, but found the instructions too complicated. Had THE hardest time even figuring out how to put it on. Have worn riot gear and tear gas masks and never a problem. The pix don’t match product— at the least the first page should have arrows pointing to the different parts. One photo shows the side pieces without the white filter (very confusing). There’s nothing about the front knob (twist it open? keep it closed?!!). Couldnt get a proper seal. No ph # to call for help. I was afraid to use it.