All UKAS 20kg Bar Weights are calibrated here at JWS to the specification listed below:

M1 +/-1000mg.


UKAS Test Weights are sent to Trading Standard to be tested and Certificated.

They must have a Serial Number or some kind of identifying mark on each weight. This number is stamped onto the weight. Contact Us if you require serial numbers to match weights you may already have. 

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.