Are all finger slides basically the same? Does it matter what size you get?
thickness and material(glass, steel, brass) will give it a different tonal quality. also metal is alot more resiliant to breaking than glass, for obvious reasons.
glass is used on electric and the thicker the glass the more sustain you will get. Brass and teel can be used on electric but dont sound that good
This perplexes me too, because you can see videos of Slash using a brass slide on his Les Paul.