This is all about the middle one in this photo: From this distance it gives an impression of being 1/2 way in-between the 1890s American made No.1 Primus and a 'normal' 2 pint No.1 type. The biggest difference of all is invisible on any photo; that is the weight. Empty, the normal No.1 on the right weighs in at 2lbs (920gms), the Soutter in the middle weighs in at an incredible 5lbs 7oz (3460gms)!!! The construction seems to be that the base and sides of the tank have been made as one piece, and the top let in from above. And from the joint on the upper edge surface of the tank is would appear that the tank walls are a full 3/16" thick!! Why?!! Everything, even the pump rod end, is heavy weight as can be seen in these detail photos (a standard detachable blow torch pump is added for comparison): The maker is given as a 'W.Soutter' of Birmingham with the date stamp '7.18', July 1918. The base has a WD arrow and 'W.H.K.', suggesting that it was made for a military contract. With supplies of Swedish stoves having been cut off by the unrestricted U-boat campaign of 1917 this is about the same time that Kenrick were producing their 'Aurora' stoves for the British army too. But where does this heavy weight monster fit into the story?