Expansion for piping slide rule Flexider 1960 The Netherlands

This is a heavy plastic slide rule with 2 separate inserts and 2 separate very tall cursors. It comes including a heavy card board box and the rule features the English language as does the plastic instruction card. Many of these design choices point towards Blundell as the maker (see for instance this: Radiation slide rule for Nuclear Fission for comparison), but there is no mentions or credit to be found. It was patented for the Dutch Company called FlexiderBenelux B.V. in the 1960’s. It helps calculation the expension af an entire pipe system in all direction by certain temperatures taking pipe length and material in account (amongst others). It is in great condition, no chips or cracks just some signs of normal use. The box has some period tape on it but is still very sturdy and complete. All parts are branded with the company name. The slide rule measures ca. 30 cm or 12 inches wide. Check the attached video on how to work your vintage man tool : slide rule operation instructions!