Step 1: Check the current frame model under the blade Step 2: Choose the model that suits you. Did you know ? It doesn't matter the blade model (with or without grooves) if you plan to replace it with your own. Step 3: Order the model that suits you, once received, nothing could be simpler! You will need a center punch or hammer and some nails. Follow our assembly video, replace the old box with the new one, and you're done! Ideal for replacing broken/worn boxes or damaged buttons. Electronic circuits and batteries not included (they will be recycled from your old box) first Check the frame model under the blade 2 steps model selection Once you know the model number of your box, choose the model that suits you using this table (the larger sizes are visible in the photo of the sheet technique) Difference between the models As a reminder, the electronic circuits and the batteries are not supplied, they must be recycled from the old boxes. Extraordinary support! Please replace your case and we'll be happy to help!