... order 4.free samples Product Name: industrial use limit switch Model No.: RL7 series & RL8 Series 1.Cotact Material: Silver cadmium ... on/off frequency is 120 operations/min) 4.Purpose: RL7 Series:Food machinery, auto packing machines, machine tool, conveying machinery, ... which need the strict protect and so on. RL8 series:Ideal for general plant facilities: engineering machinery,conveyer machinery, ...