Ultra Articulating Keyboard Tray by ESI Ergonomic Solutions Keyboard Combo Solution, for radius corner work surfaces, position the keyboard closer to work area (Qty of 1 in Cart = 1 Keyboard Combo) Combo AA360 Articulating Arm With PL217 Switch-n-Click Convertible Platform. AA360 Articulating Arm, 21" glide track, Lift and Lock, 7" height adjustment. High 2.5" above track, Low 4.5" below track.