Universal ( dont know original Manufacturer)  counterbalance weight with resettable graduations to suit tonearms designed for weight with an internal  spiral groove..

Aperture is 10mm but suspect the tone arm  diameter  may still  fit  projections of the order of 8mm 

Weight is 105 grams 

Diameter 25.4 mm  ( 1 inch)

Overall length 35.6 mm  ( 1.42 Inches)