This 29 cm or 11 3/4 inch slide rule was made in England by the Relay Company. It has the designation T1051 on the back with extra information. There are also 2 windows on both side. It has scales on the front and on the back of the slider L and LL 1-3 and scales A,B,C1,C,D, S,T,K,P on the front. It is in overall good condition, no warps, no chips, some signs of use and age (some ink spots). The metal with glass cursor is fine as well. It also comes with the original signed sleeve in good complete condition. Check the attached video on youtube on how to use a slide rule!