Types of Reels
Shipping reels are used to transport film from depots and archives to venues. They can be made of steel or plastic, though plastic shipping reels are much more common. Shipping reels are for SHIPPING. They are not for PROJECTING. This is a common misconception.
Show reels, also called "house reels" are used for projection. Venues should keep a set of house reels in excellent condition for projection, and replace as necessary.
Split reels are used transfer film on cores to reels. Split reels are not suitable for projection.
Reels come in sizes as small as 50 feet (typically for 16mm trailers) to as large as 18,000 feet for long-play tower systems or double mutts. Reels with hubs smaller than 4 inches are generally not suitable for projection. It is important that reel hubs are perfectly round or film can become damaged from an uneven wind.