SLIP-OVER REEL SEAT SLEEVES. Support For Larger Reels. Machined from the finest marine aluminum, AFTCO Slip-Over Reel Seat Sleeves are designed to support the forward reel braces found on many of the larger big game reels. Measuring 2 inches in length, they are available in three sizes and two finishes — Silver anodized or Hard-Coat Black anodized.