harsh environments essential types covers serve cnc machines smooth motion lightduty protection bellow making tight seal bellow forms mounting type lightweight easy accordion making bellow design coated textiles fabric rubber heavyduty machines cover slides bellow cover coolant splashes shielding components moving parts telescopic cover bellow cover excels telescopic steel covers maintaining machine efficiency protect moving parts telescopic cover offers telescopic steel cover solid heavyduty coverage protecting precision components dust chips coolant ensure optimal performance heat sharp chips overlapping steel plates stroke length shape guideways ball screws basic purpose covering