| Deciding factor | Screwless light shelf | Medium-duty shelf |
|---|---|---|
| Rating | ~80 kg / shelf | 150 – 500 kg / level |
| Assembly | screwless, tool-free | bolted uprights, keyed boards |
| Relocate | knocks flat fast | heavier, slower to move |
| Stability at load | shear limit at key | bolted holds heavier level |
| Best fit | light goods, movable room | boxed stock, hand/trolley |
Why not just always buy medium-duty?
Medium-duty costs more per bay and is heavier to relocate; for goods far under its rating the extra capacity is paid-for weight you never use, while a screwless unit gives the same manual layout cheaper and knocks flat for a move.
Decision rule
Both are manual shelves, and the difference is a single rating: a screwless key transfers a light load cleanly and reassembles anywhere, but past its shear limit the frame would shear rather than carry, which is where a bolted upright and a rated per-level medium-duty shelf take over for boxed, heavier hand-handled stock. Choose screwless where the goods are light and the room moves; choose medium-duty where the per-level load climbs and the shelf stays put.
All figures on this page are illustrative sample values, not measured specifications.