5/8 inch size banjo bridge........This is the most common size and likely what you have unless you or someone else before you switched it out.

.656 bridge for banjo .......This is the next size up, it would be good to get one of these. For instance, if you used a 5/8th bridge and the string action was too low, or if your string action seems to shift and go down too low sometimes causing your strings to buzz, (weather can cause slight neck angle shifts) Then you'll have a backup for that, that is what I do, I keep a higher bridge handy in case I get any string buzzing.

11/16th 5-string banjo bridge.....This is the size that many pros use and what I often use. One of the reason more experienced players use these is because we like the higher action for more volume and also when playing with a band you use a capo a lot. When using a capo, higher action keeps the action feeling normal and without a drop in volume. If you are using a 5/8th bridge now, and you want to switch to 11/16th, your banjo neck will need to be adjusted, so consider that when you make this purchase. Adjusting of the neck should be done by a professional or with great care.

3/4 inch size banjo bridges.......I also use this size, depending on where my string action is.

9/16 and 1/2 inch are the smallest sizes. The 9/16ths is just below the standard 5/8's. This size could also work well as a second bridge in case with weather changes the string action grows and you want a quick remedy for slightly too high of action when using a 5/8th's. The .656 works well in the same regard as a second bridge in case the action temporarily gets too low using a standard 5/8ths bridge with the weather changes if you hear a buzz or rattle.

Crowe Spacing is slightly wider and works well for pickers with longer fingers. It also spreads the strings out slightly on the neck and can be a nice feature for banjo players that wish their neck was wider. Just spreading the strings a bit with the crowe spacing makes a significant difference in feel in that regard and can be a less expensive and more practical solution than ordering a custom wide neck or re cutting the nut.

I hope that wasn't too much information. To be practical and to the pont, if you are just replacing the bridge you have, 5/8ths is the standard size and what most folks use. I also recommend the style II. The Snuffy Smith Style II is a non invasive way which does not affect the tone to compensate for the G, third string from fretting sharp. This is an inherent problem for all 5 string banjos some worse than others but never the less, there have been many approaches for a remedy for this and this is the most practical and best one I've seen. Thanks, Ross Nickerson