Exclusive double clamp design for a no slip fit. Pro-Feed elbows are constructed of virtually indestructible nylon. Available in 7/8" - or 1" Universal with insert sleeve that fits either. 7/8" is for the more 7/8" inch feed neck and 1" loader - the 1" is 1" on both ends and includes an insert sleeve that allows it to be used with 7/8" feed necks (the insert can also be used for 7/8" loaders and is available upon request with 7/8" elbows as well!). *Note: our remaining inventory of Grey elbows is a Light Blue/Grey tint.