I have always found fuze designs and technology fascinating and have purchased a few INERT ones here and their over time. I have no clue what this went to or who made it, but the way it works is pretty interesting.
It is engraved L81 A1 10 DX-6 0 and looks to be calibrated 0 - 60 which I am assuming is seconds? Internally it seems to use 4 ball bearings that travel against a grooved inner cog thing and a matching grooved channel running against the fuze body wall. Hope that made some sense. If not, hopefully the pics may.