Base UD Intrance Kit
This kit allows the modification of at least one brood box plus another box (brood or super) as required.
There is no need for a 'standard' floor and a piece of wood that fits under the main brood box is all that is needed.
Typically 3 UD intrances are used in the brood box, but small colonies can be limited to 1. An entrance that provides access to the brood area is important so that the bees can stimulate the queen with the nectar/pollen flow. If the enrance is too far from the brood nest the laying rate is decreased.