Details IMS Precision Ridgeless Double Portafilter Basket, 18/20g A shorter, ridgeless IMS competition basket built to maximize puck contact and even extraction, the flat-bottomed, cylindrical shape was engineered by I.M.S. to balance the coffee bed's height-to-base ratio for cleaner flow and easier drying/expulsion. SPECIFICATIONS Height: 26 mm (shorter than standard) 70 mm outside diameter at the rim, 60 mm body, sized for 58 mm tampers Ridgeless, flat bottom, 49 mm perforated area with exactly 715 laser-precise 0.30 mm conical holes Finished by wet vibrofinishing with ceramic media, corncob-dried, then electropolished for a smooth, non-contaminating surface Material: stainless steel COMPATIBILITY Fits: 58 mm portafilters (a thicker, 1.2 mm portafilter basket seat is recommended for the tightest fit) Also listed as: Kees Van Der Westen #MSR-A130-20 INSTALLATION Drops directly into a compatible 58 mm portafilter, no tools required, though a thicker-walled portafilter is recommended for the snuggest seat. PRO TIPS IMS's patented perforation pattern is genuinely different from generic laser-cut baskets, the conical hole shape and exact 715-hole count are tuned specifically to this basket's height and diameter, which is why swapping brands can shift your shot timing even at the same dose. Because it's shorter than a standard 18/20g basket, use it with a properly leveled tamper stroke, the reduced puck height makes channeling from an off-axis tamp more noticeable in the cup.