Originally Posted by Geoff Hannis

With reference to the attachment you provide, I have no idea what E2, F1 et al mean.

OK ... I've found something now.

It seems that Marsden use M1. smile

Note the ± 0.005% accuracy of the 5 kg M1 iron calibration weight (but note also the price)! This complies nicely with the attachment at Post #74654 (eg, 5 g at 100 kg - or 5 ml of water).

If you don't inspect ... don't expect.