Summary (1) Purchasers are@ in some instances@ interested in having specifications to use as checks or uniformity of deliveries@ and there is a practical way to do this if it is worth the expense; viz.-the simple physical specifications used by the supplier himself as manufacturing controls; (2) Purchasers are interested in a purchasing practice that assures the best performance in service; (3) Laboratory test methods now available are not@ of themselves and without performance tests@ a reliable guide to performance in service; (4) With rare exceptions@ purchasers are net in a position to conduct or interpret the eleborate engine or gear tests required for even the preliminary evaluation of oil performance characteristics; (5) The practice that has proved most successful is the purchase by brands warranted by the supplier to meet the purchaser's established standards of performance in terms of the lubricant's.