This is the replacement side bearing for the Carter 2300, 2400, Guidall 500, and Guidall 600 guides. Early models of the 2300 used a smaller bearing.  The od on that one is 22mm.  Let me know if you have the smaller bearing on your set.  There are no shipping charges on this item if shipped  to a US address.  I do ship internationally, just email me your location and I will quote shipping to your country.  See the list of countries that I do not ship too.