bought with other weights at the boot sale , screams Ysart Brothers to me as very dark glass compared to strathearn and later vasart, also has fire polished base with slight off centre concave , large size at around 3 and a quarter inches wide and about two and a halve tall , cost a quid so im sure its a bargain, the third picture shows this weight to the left with a later weight to the right to show difference in glass darkness