Bearing closures are like walls that protect the bearing from outside debris and help keep lubricants inside the bearing. Typically quad bearings come with one closure, which is either a bunna rubber seal (aka rubber shield) or metal shield. In rare occurrences plastic shields could also be used in the same way as metal shields.

There are 2 types of metal shields– 1) pressed in non-removable metal shields and 2) removable metal shields held in with a C-ring. Pressed in shields do not allow for easy, if any, bearing maintenance.

Bunna rubber seals are considered a better choice for sealing lubricants in the bearing and for not allowing contaminants, like dirt and moisture, to enter the bearing.

There are three types of rubber seals: light contact, non-contact, and labyrinth. Located on the inside edge of the bearing seal is a thin flap of rubber. This flap is either lightly touching or not touching the inner ring of the bearing. These are known as "light contact rubber seals" or "non-contact rubber seals" respectively. Light contact rubber seals do a better job at protecting the bearing and keeping lubricant in. This light contact does not create any noticeable reduction in speed while rollerskating.

The third type of seal (and our favorite) is the labyrinth seal. This seal sits in a groove machined into the inner race and approximately doubles the distance required for dirt/lube to travel. This translates into a much longer bearing life.