A pair of knee protectors - comfy and durable. Genuine US armed forces surplus, these are proper good stuff.
Made of strong Cordura fabric, with foam padding hard plastic outer piece (coyote color protectors have either black or coyote colour cups). Secured to the knees with adjustable velcro straps.
Three sizes: Small, Medium, and Large. A rule of thumb would be: if you got chicken legs, get Small. Most people will do fine with Medium. If you got trunks for legs, get Large.
Used but still perfectly serviceable.