This is what will keep you going and getting the wrong pair will turn heaven into hell.
1. B0- Non-Rigid boots you can't use with a crampon
These are you standard walking boots with softer soles and aren’t designed for technical or winter walks in the mountains. The overwhelming majority of boots fall under this category.
2. B1- Winter walking boots- These can take a C1 crampon
These boots have a rigid enough sole to take a crampons and are designed for winter on the mountains or summer glacier crossings They aren’t stiff enough to be used for technical mountaineering however.
3. B2- Mountaineering boots- These can take C1 or C2 crampons and are used for technically mountaineering. You can tell this type of boot by the fact they have a heel welt.
Used for technical mountaineering and winter climbing up to Scottish Grade III. Come with a very rigid sole, great for winter but awful on pavement.
4. B3- Ice climbing/ Expeditions boots- Can take C1, C2 and C3 crampons.
Completely rigid soles used for expeditions into higher ranges (such as the Himalaya) and for pure winter climbing (Scottish Grade III-X). Due to the construction of these boots they can’t be used comfortably in ‘lesser’ conditions. These boots come with a heel and toe welt.
1. C1- This normally use the 'strap on' system.
These are used for winter hill walking/ summer glacier travel. They are not suitable for winter climbing in as they typically have only 10 points, with the front points being quite short. Can fit onto B1-B3 boots though best used with a B1.
2. C2- These are normally the 'Hybrid'/ ‘semi-step in’/ ‘semi-automatic’ system.
Used for technical mountaineering and lower grade climbing (I-III). Can fit onto B2 and B3 boots but not B1. This is your most common type of crampon as it allows for more versatility in activity.
3. C3. Use the ‘step-in’/ ‘automatic’ binding system.
Used for pure climbing or expedition. These crampons sometimes come with 14 points and can have only a single (Mono) point on the front instead of 2. This Monopoint allows for technical climbing moves normally reserved for pure rock climbing. They attach to B3 boots.
Match the boot to your activity based on length, terrain, time of year and likely weather condition. This will get you the right boot for what you are going to be doing. Then match the crampon to the boot.
Example: If you want to do technical mountaineering in winter then you get a B2 boot and C2 crampon.
While higher boots can take lower crampons (B3 can take C1) it is best to match the crampons as the binding works best with the boot and your activity. Some manufacturers do offer the same crampon but with different binding systems. It is important to note that while this will help the crampon fit the boot better the binding doesn’t make the crampon, or boot, better for different activity levels.