ThunderShirt® for Cats is the original, natural calming solution for cats. The patented design applies a gentle, constant pressure that has a significant calming effect on most cats. Using pressure to relieve anxiety in people and animals has been a common practice for years, like swaddling an infant, or using a weighted blanket. The ThunderShirt® for Cats is perfect for reducing anxiety during vet visits, nail trimming, travel, or other general anxiety issues. New in box. M (9-13 lbs). Non-smoking home. Retail at $40.