3 x original Apple silicone dome for the M2452 coloured USB keyboards which perform the spring/lift function of the keycap and well as pressing the contact on the keyboard membrane. This is the smaller orange version used only on the top row and arrow keys. A fairly common fault on this keyboard is keys not springing back when pressed. This is cause by the cylinder on the rear of the keycap cutting through the silicone dome and is easily repaired by replacing the dome using a pair of tweezers.