5 x 10 mm Ruby Ball Tip
Buylink:
http://www.shop.emicroscribe.com/product.sc;jsessionid=6F29DACA9EB4C7C9D756BC03B9250B94.qscstrfrnt04?categoryId=14&productId=111
Cost:
$72
Summary:
Dia .1968" ( 5 mm) Length to center .3937" (10mm), Delta offset .3937" (10mm)