I believe that the seat tube of the 93 Explosif was Concept, and it consequently had a Concept sticker, but I have always assumed that the Ultrastrong sticker on the 94 Explosif meant that the seat tube was changed to Ultrastrong for 94. Except on Ian31's bike apparently, which must have a Superlight seat tube.greenstiles":t9erve8a said:If the sticker has to be true to the tube that is stuck to.................then why does it say 'ultrastrong' and not 'concept' which is what that seat tube is made of............top tube being 'ultra light' only the down tube is 'ultrastrong ??? or is 'ultrastrong classed as a combination of tubes ???