Will FJÄLLBO Shelf unit, black, 20 1/8x53 1/2 " fit in an Audi A4 Avant 2022?

The A4 Avant pairs a wide mouth with real height: the opening measures 40⅛″ across and 33½″ tall, so upright boxes pass through without a tilt. The floor gives you 41⅜″ with the rear seats up and 72″ once they fold, a gain of 30¾″, with 39″ between the wheel arches at the tightest point. The lift-over sits at 24¾″ and the floor is only 2″ below it, almost level, so long boxes slide in instead of dropping in. Tall furniture cartons and long flat packs both do well here; extra-wide boxes meet the 39″ pinch first. Slide heavy loads across the sill on a blanket rather than lifting them over.

FJÄLLBO ships as one flat box, 53″ long by 14¾″ wide and just 3¾″ thick, at 24 lb 4 oz. The length is the only real problem: 53″ rarely clears a trunk opening with the seats up, so plan on folding the rear bench in anything smaller than a wagon. The box itself is a one-person carry, but the slim profile flexes if you hold it by one end; support the middle or carry it on edge. Angle it through the tailgate diagonally, long edge first, and let it lie flat on the folded floor. Check the label against your order before you leave the racking aisle.