Hi! As a music teacher, I often need somewhat unusual organizers. I designed a 9-slot storage rack for guitar capos, and they fit perfectly. 

The best part: students are now automatically returning them after use—so no more capo clutter in the classroom! 🙂

The slots are 15 x 85.6 x 25 mm (L x W x H) 

Capo used in the picture: ‘K&M 30910’