Andrzej Andrez wrote: > I thought that you own i1 Pro 2 and noticed that there is (or not) a > sticker with certification due date like is on i1 Pro. What came with it was a "Certificate of performance", which was "ISO 9001 Certified". This appears to be a re-statement of the instrument specifications. The certificate states "X-Rite recommended calibration interval: 12 months". Graeme Gill.