Blum 563 Tandem Plus Blumotion 21" Soft-Close Full Extension 90 lb Undermount Drawer Slide, Zinc, 26280402

Full Extension and Soft-Close in the Most Common Drawer Depth

The Blum TANDEM plus BLUMOTION 21 inch slide is a full-extension, soft-close undermount drawer slide built for the 21 inch drawer box — the depth that appears most often in kitchen base cabinets. Concealed beneath the drawer box, it runs on roller bearings, closes silently on Blum's integrated BLUMOTION damper, and carries 90 lb per pair.

Key Features

• Full extension brings the entire 21 inch drawer out to the cabinet face, so rear contents are fully within reach.
• Integrated BLUMOTION soft-close catches the drawer in the last inch of travel and settles it shut with no slam and no noise.
• 90 lb weight capacity per pair handles loaded pots-and-pans and utensil drawers without strain.
• Roller-bearing carriage on steel members delivers a smooth, consistent pull across the full 21 inch travel.
• Fits face-frame and frameless cabinets — the same slide works in both construction types with the appropriate mounting hardware.
• 3/16 inch side clearance keeps the concealed profile tight without requiring non-standard box sizing.

Where the 21 Inch Length Works Hardest

Base kitchen cabinets — particularly the 24 inch deep standard — are the natural home for a 21 inch undermount slide. The length suits the drawer box depth that cabinet shops cut most often, making it the go-to spec for production kitchen runs. It also covers bathroom vanity drawers with deeper cases, laundry room base drawers, and utility cabinets where full rear access matters. The full-extension travel means nothing hides at the back: spice pulls, cutlery drawers, and prep-area utility drawers all benefit from a slide that brings the whole box out.

Construction and Finish

The slide is built from steel with a zinc finish — a functional, corrosion-resistant coating suited to indoor cabinetry. Because the slide rides beneath the drawer box, the finish stays out of sight during use; its job is protecting the steel through years of daily cycles, not decorating the interior. The roller-bearing mechanism provides smooth travel under load without the weight penalty of a full ball-bearing rail.

Who Should Specify This Slide

Production cabinet shops building standard kitchen lines will find the 21 inch length the most frequently pulled size in the TANDEM plus BLUMOTION family. Custom shops and installers working on kitchen remodels specify it for the same reason: it drops into the most common base-cabinet configuration without any dimension adjustment. Homeowners upgrading an existing kitchen can use it as a direct replacement for worn slides in cabinets with 21 inch drawer boxes built to 1/2 to 5/8 inch side thickness. It fits both face-frame and frameless construction, so the same part number covers the full range of common American cabinet types.

The Right Slide for the Most-Used Drawer Depth

Match the 21 inch TANDEM plus BLUMOTION to a box built to Blum's spec, add the locking devices and any rear brackets your cabinet construction needs, and this slide delivers full rear access and silent closing for the life of the cabinet.