This Lens Savers® adapter is designed for Amada laser systems using a cutting head where there is insufficient room to mount the adapter directly inside the OEM lens mount, such as in the cassette style lens mount used in the Amada 3015 and 2415 which slides into the head from the side of the assembly and the Amada Gemini. This is for use with 5" FL.The channels in the Lens Savers® adapter allow assist gas to circulate in the head and allow pressure to equalize around the Lens Savers® window. Allowing assist gas circulation accomplishes two objectives. First, the assist gas pressure would exceed the pressure rating of the window if the pressure did not equalize, causing the window to break. In addition, the assist gas aids in the cooling of the lens and the window.