I prefer the Hamilton Fretspanners. I use these and most capos with acoustics. What I like about them is they have a wide clamp and the ledge of rubber. The concept is to clamp the strings to the fret and the guitar is always in tune. The drawback to these style of capos is the width of the clamp prevents you from capoing at the first fret. It is to wide and hits the nut. Check them out. they are pretty inexpensive.