The Consultative Committee for Length (CCL) identified several key comparisons in the field of dimensional metrology at its meeting in September 2008. It decided that the formally individual key comparisons on short gauge blocks and on length bars should be combined under the designation CCL-K1. Key Comparison EURAMET.L-K1 was instigated following a decision at the 2010 meeting of the EURAMET Length contact persons held at SP Technical Research Institute of Sweden. A goal of the CCL key comparisons for topics in dimensional metrology was to demonstrate the equivalence of routine calibration services offered by NMIs to clients. The comparison was coordinated by the BEV (AT) as the pilot laboratory with substantial help by PTB (DE) for the long gauge blocks stability measurements.