The convex-bottom, higher-capacity sibling of the B682TH24.5M in IMS’s
Gaggia-fit B68 series (Ø 68mm border, 2mm narrower than the B70, standard
Ø 58mm tamper). At 26.5mm height it takes larger doses than the 24.5mm
variant — IMS rates it 17-23g depending on roast — so check headroom against
the stock Gaggia shower screen with bigger doses. Verified against the
official IMS product page and catalogue on 2026-07-06.
FAQ
What size portafilter is the IMS B68 Competition Convex 2/3 Cup (B682TCH26.5E) for?
It is a 58mm basket, 26.5mm deep, for 58mm portafilters.
Is the IMS B68 Competition Convex 2/3 Cup (B682TCH26.5E) pressurized?
No — it is a non-pressurized (single-wall) basket, for freshly ground coffee.
Does the IMS B68 Competition Convex 2/3 Cup (B682TCH26.5E) fit 54mm machines like the Breville Barista Express?
No. It is a 58mm basket, so it does not fit Breville's 54mm machines or any 54mm portafilter.
Which machines does the IMS B68 Competition Convex 2/3 Cup (B682TCH26.5E) fit?
Gaggia Classic GT; Gaggia Classic Pro (E24) — each confirmed against manufacturer sources (listed below).
Sources
https://imsfiltri.com/prodotto/b682tch26-5e/(archived) — Official IMS Filtri product page ('Competition - Convex Bottom', B68 2/3 cups), read firsthand 2026-07-06. Specs verbatim: 'Border: Ø 68 mm', 'Body: Ø 60 mm', 'Height: 26.5 mm', tamper 'Ø 58 mm', ridgeless, convex bottom that 'collects coffee towards the center', '715 holes in hexagonal pattern' of Ø 0.30 mm over a 'Ø 49 mm area optimized for convex shape'. Capacity 17/19g (dark roast) to 20.5/23g (light roast).
https://www.imsfiltri.com/IMS-competition-Catalogue.pdf(archived) — Official IMS Competition Series catalogue, read firsthand 2026-07-04: 'B68 (BORDER Ø 68 mm) CARIMALI, GAGGIA, LA CIMBALI. The body of B68 filters is the same as B70 filters but with a border that is 2 mm narrower for a better fit in portafilters of the quoted brands.'