This unit is similar to the #3A but does not use the Rocky's tubing. The hub is 4" and will take the 4" o/d Aluminum Irrigation type tubing (not supplied by Rocky's). This fits inside the 4" Hubs. #3 Portable (4" Hubs) Ground clearance to underside of tube is approximately 8.75". Shipping weight is 13.5 lbs.   Strong Die Cast Aluminum Construction Baked Enamel Finish Enhances Any Pool Easy To Use, In Most Cases By One Person Quality Castors For Ease of Portability Positive Anchoring System Light Weight Yet Extremely Strong Not Effected By Sunlight Or Freezing Cold Quality Hardware FULL 10-YEAR WARRANTY PROBLEM FREE #3 Residential Portable Installation Instructions (2pgs. 279k) You will need the Adobe Acrobat Reader to view this file. Click here to download. © 2001 Rocky's Roller Systems Inc.   All rights reserved.