This listing is for 4 clamps the phot r background muslin clamp is essential for any photography studio these have immensely strong gripping power and will hold almost anything in place including cables support poles and backdrops these are perfect if you have bought any photographic backdrops maximum jaw capacity is 50mm this clamp has a sturdy grip with gentle pivoting pads that adjust to the grip surface small teeth on the inner diameter hold muslin cloth or paper backdrops in place