Given a choice, a cat scratches upwards. The whole point of the movement is the stretch that comes with it: front paws high, spine long, weight pulling down against something that does not move. In a flat with no spare wall, the thing that does not move is usually the arm of the sofa. Moving the scratching surface onto the window glass puts it at the height a cat already wants to reach.

Two sisal-wrapped columns give the coarse, fibrous texture cats generally choose over carpet or cardboard, and sisal wears down in strands rather than shedding sheets across the floor. The suction cups fix it to glass or any smooth, non-porous wall without tools, fixings or a landlord conversation. That fixing is only ever as good as the surface underneath it, which is why a wipe with something that leaves no film, and a firm press to seat each cup, matters more than it sounds.

• Double-column sisal scratching surface
• Suction-cup mounting for windows and smooth walls, no tools needed
• Around 24.6 x 22cm, so it fits a narrow pane or the gap beside a unit
• Suited to smaller cats, up to roughly 5kg
• Twelve configurations listed, from a single pole to lying platforms and jumping steps

Two things worth knowing. And re-seat the cups every few weeks: suction creeps in a warm window, and a post that gives way once will put a cat off it for good.

Who it's for: Owners of small to medium cats in flats and rentals, where a floor-standing tree will not fit and drilling is not an option.