The product started with "F" series tapchangers in collaboration with Ms.Fuller Electric Co - UK.These tapchangers were based on latest technology of their time and still satisfy the needs of present customers. Even today, the F33 & F66 are highly familiar names in the OLTC market. Over the years, the product has undergone various design upgradations satisfying the new challenges and requirements of the customers. The product, a high speed resistor type is designed for use with 3 ph distribution substation transformer. It can be bolted directly to a port flange on the transformer.