Keep parts organized when the instrument is disassembled. This block is designed so the longest rods are located at the back to avoid reaching over them. There are labeled holes for the 27 most common rods, and places for 3 miscellaneous rods. There are holes for rollers up to 6mm in diameter which will accommodate most makes and models of saxophones. This rod block can be used for any size of saxophone.The blocks are durable with a surface that is resistant to oils and grease. Dimensions: 7.13 x 4.7 x 0.73 inches (18 x 12 x 1.84 cm)