The only cage that brings its own Allen key
ROCKBROS Polycarbonate cage, 30–35 g (1.1 to 1.2 oz), with wrench
A polycarbonate bottle cage weighing 30 to 35 grams, supplied with two screws and a 3 mm (0.12 in) Allen wrench.
What you are getting
A single polycarbonate cage with two screws and a 3 mm (0.12 in) Allen wrench, with arms that wrap the bottle. 30 g (1.1 oz) on the shipping record, 35 g (1.2 oz) in its own bullet. $9.89.
It publishes two different weights
“Made of high quality PC material, ultra-light, only 35 g (1.2 oz).” The shipping record for the same listing says 30 g (1.1 oz).
Five grams, which matters to nobody except as a reminder of which figures on a listing are checkable. Both are lighter than the PRO BIKE TOOL machined alloy cage at 48 g (1.7 oz), and both are heavier than the ThinkTop carbon at about 25 g (0.9 oz).
So polycarbonate sits between them — which is the point of the material.
Polycarbonate, and the claim an alloy cage cannot make
“Has a nice finish that doesn’t scratch or mark the bottle”, and “will not attrit the bicycle frame”.
Two surfaces protected: the bottle and the frame. A plastic cage can say this; the CNC alloy cage on this page hedges with “less likely to scratch”, and that difference is real — bare or anodized alloy arms do mark a plastic bottle over a season.
Polycarbonate is the same material family as the Rose Kuli cage already published on this shelf, which is the one existing fiche this most resembles.
“Comes with 1 × 3 mm (0.04 × 0.12 in) Allen wrench and 2 screws.”
The FiveBox cage on this page states that its 4 mm (0.16 in) hex key is not included; the CNC and PRO BIKE TOOL cages supply screws and no tool. This is the only cage in this survey that arrives able to fit itself, and the stated fitting time is “less than 60 seconds”.
Note the bolt size difference: 3 mm (0.12 in) here, 4 mm (0.16 in) on the FiveBox. Not interchangeable keys.
It says the thing every one of these listings should say
“IMPORTANT: Check if your bike frame has threaded holes before you buy.”
In capitals, in the third bullet. A frame without bottle bosses takes no bolt-on cage at all — and the SKS strap-mounted cage already published on this shelf is the answer for one, as the introduction to this page notes: strap-mounted cages are “the only answer for a frame with no bottle bosses at all”.
Two other listings here mention threaded holes in passing. This one puts it in capitals.
The bottle range is the vaguest on this page
“Not only suit for standard size bike water bottles, likes 20, 21 ounce size, but also the disposable water bottles or coke.”
Twenty to twenty-one ounces is 590 to 620 ml — a narrow pair of figures, and then an open-ended mention of disposable bottles. No diameter, no range, no maximum.
Compare: FiveBox 68.9–76.2 mm (2.71 to 3 in), PRO BIKE TOOL 500–950 ml with ±5 mm (0.20 in) flex, ThinkTop 71–75 mm (2.80 to 2.95 in). This is the one cage here you cannot check a bottle against.
Top entry, as all five are
And the buying advice on this shelf applies: measure the gap between the bottle boss and the top tube, because on a small frame a top-entry cage and a tall bottle do not come apart.
What is not published
No bottle diameter, no maximum volume, no bolt spacing, no cage dimensions, and the weight is given twice as two numbers. Two of the five bullets end by asking the buyer to contact the seller about missing parts.
Availability
Read on the day this page was built: $10 at the American Amazon shop.
Read from Keepa on the day this page was last revised; stock and price both move without notice.
Prices quoted in this text were read on 2026-10-06. The live price is at the top of the page.
