Brompton folding bikes use product codes such as S2L, M6R etc. The product code refers to the bike’s handlebar model, the number of gears and whether there are fenders and / or luggage rack.
M is the most popular model, great for both the city and the countryside.
H is the same shape as the M bar, but 6cm higher.
S provides a low and sporty riding position.
P is designed for longer trips, offering a wide range of hand positions.
The number of gears available are as follows: 1, 2, 3 or 6.
E model is without fenders.
L model has fenders.
R model has both fenders and a rear luggage rack.
So, as an example, the Brompton M3L has the M-handlebar, 3 gears and mudguards. This is the most commonly purchased model, along with the saddle mounted cover bag.