New Old Stock Shimano 105 chainring from the 1050 series of the late 1980s / early 1990s, but also perfect for any Shimano chainset (or any other brand in fact) that has 130 BCD. Gives you that extra hill climbing power on the old 42/52 chainring setup.
3/32" is used for double & triple chainsets but can also be used for single ring chainsets. 1/8" is generally used for track chainsets & some single chainsets too.
Please be sure to check that the BCD (Bolt Circle Diameter) matches that of your crankset, otherwise the chainring will not fit. If you need help measuring your BCD, good ol' Sheldon Brown will be glad to be of assistance here: http://www.sheldonbrown.com/gloss_bo-z.html
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