# Kryptonite Combo U-Lock, 12 mm Shackle, 4-Digit Code

Source: https://www.ranked10.co.uk/fitness/best-bike-locks/kryptonite-combo-u-lock
Ranked #10 in "Best Bike Locks 2026: 10 Ranked, Diamond Beats Gold on Price": https://www.ranked10.co.uk/fitness/best-bike-locks

- Price: £18.03 (checked on Amazon UK on 2026-09-19)
- Amazon rating: 4.3 from 1,069 ratings
- Buy on Amazon: https://www.amazon.co.uk/dp/B0BDGK2DWG?tag=ranked10-21

The Kryptonite Combo U-Lock is the cheapest of the ten locks in this guide at £18.03, and it is the one that makes the price-per-millimetre argument plainest. Its shackle is 12 mm of hardened steel. The £299.99 Hiplok at the other end of the list claims 32 mm — 2.7 times the steel for 16.6 times the money. The Kryptonite does that without a key, on a 4-digit resettable combination.

The figure that does not sit right is the Anti-Theft Protection Offer: this listing quotes it at 'up to $500', in dollars, on a page priced in sterling. The £38.75 Kryptolok in the same guide quotes the same Kryptonite programme at £1,000, in pounds. Both are Kryptonite's own numbers; only one of them is in the currency you are being asked to pay in. Everything on this page is taken from the Amazon listing — price, specifications and reviews — and not from any test we have run.

## Specification

| Field | Value |
|---|---|
| Price | £18.03 |
| Customer rating | 4.3 out of 5 from 1,069 ratings |
| Shackle | 12 mm hardened steel, the thinnest of the ten picks |
| Locking mechanism | 4-digit resettable combination, no keys |
| Interior / exterior dimensions | 4" x 8" / 6.5" x 9.5" |
| Anti-Theft Protection Offer | Up to $500 upon registration, quoted in dollars on a sterling listing |
| Best Sellers Rank | 12 in Cycling U-Locks |
| Control Method (as listed) | Touch |

## Questions people ask

**Does the Kryptonite Combo U-Lock need a key?**

No. The listing describes an easy-to-use 4-digit resettable combination and states there are no keys for you to lose, and the spec field lists the lock type as a combination lock.

**What are the dimensions of the Kryptonite Combo U-Lock?**

The listing gives a 12 mm hardened steel shackle, interior locking dimensions of 4" x 8" and exterior locking dimensions of 6.5" x 9.5".

**What happens if I forget the combination?**

Kryptonite's Combo Safe Program lets you register your unique 4-digit code on the Kryptonite website, after which the customer service team can help. The listing does not say what happens if the code was never registered.

**How much is the Anti-Theft Protection Offer worth?**

The listing states up to $500 reimbursement upon registration — a dollar figure on a product priced at £18.03. The £38.75 Kryptolok in the same guide quotes the same Kryptonite programme at £1,000 in sterling.

**What can I use the Kryptonite Combo U-Lock on?**

Kryptonite lists bicycles, sports equipment, gates and fences, tool boxes and ladders, grills and lawnmowers, skateboards and truck beds.

**How is the Kryptonite Combo U-Lock rated?**

4.3 out of 5 from 1,069 ratings, and it sits at number 12 in Amazon's Cycling U-Locks best sellers rank. The breakdown shown on the listing has 71 five-star entries against 7 one-star.