Quads - "Quads" has now become the generic term for the set of marching tom toms used by marching bands. The function of these drums is the same as the older tenor drum - to fill out the middle register between the snares and basses. The drums themselves are very different though - much more shallow and with only the single head. Though usually used in sets of four (hence the name "quads") they are often used in in sets of five (as shown in the photo) or even six.