These Deering Banjo Spikes are used to capo the 5th string of your banjo. Tiny and unobtrusive these spikes will allow you to capo the 5th string of your banjo easily. The most common approach is to install spikes at frets 7, 9, and 10, which allows you to capo the 5th string to notes A, B and C respectively.
They are installed by drilling a tiny hole in the fingerboard and carefully tapped into the hole.
Sold in packets of 12.