All UKAS Hexagonal Weights are calibrated here at JWS to the specification listed below:

M1 +/-50mg. 


UKAS Test Weights are tested by an independent UKAS Accredited test facility. 

They must have a Serial Number number stamped onto the weight. This number is automatically generated by JWS or, if you have an existing set of weights and want the serial numbers to follow on or match those you already have in some way, please contact us once order has been placed. 

Only one UKAS Certificate is needed per batch of weights on the same order. Please remember to add this to your basket available back on the Test Weights page.