Telescopic / extendable spirit level

I recently installed a rail for a shelf inside a confined space and found my existing spirit levels were either too long or too short. I came up with this design that extends from around 300 - 600mm to solve that. It requires a 15mm x 15mm square, 40mm long spirit level which are available on Ali Express. You'll also need a bit of adhesive like superglue. Note that the parts on the plate are for a single arm so you'll need to print two copies. I recommend just printing one first to check clearances and make sure everything slides together. Before trying to assemble make sure the brims are removed fully on both the outside and inside. Start by fitting the thinnest section inside the middle section and then putting that pair inside the largest section without gluing anything at this stage. In the pack I bought there was some variance between the spirit levels so do the assembly on a flat surface to find the most accurate level and to keep things aligned while the glue dries. The