Cheap And Discounts 2AI2RO 2-channel Analog Input 0-20mA/4-20mA 2-channel Switch Output RS485 Modbus RTU Lightning Protection Anti-interference Wholesale. Buy Directly From Merchant Coolco Store. Enjoy ✓Free Shipping Worldwide! ✓90 Days Buyer Protection. ✓Easy Return. ✓Money Back Guarantee.