Read the E31 geometry literally
Urnex declares the selected E31 tablet 15 mmin diameter and 2 gin mass. Those specifications help distinguish it from other tablet codes. They do not establish that it belongs in every machine opening, basket or cleaning disc. Cycle Ledger has not measured a tablet or fitted it to equipment. A product photograph can identify a form, but it cannot prove an approved chemical-and-machine combination.
Keep geometry and formulation separate
Two tablets can be similar in diameter while differing in mass, ingredients, dissolution behavior or intended task. A different Cafiza code is not automatically equivalent to E31. The site does not recommend breaking, trimming or combining tablets to make one fit a compartment. It also does not infer a machine dose from a diameter comparison or use a generic tablet count to override a model instruction.
Read the exact device requirement
The reviewed BES870 booklet describes a cleaning tablet in a particular cleaning-cycle context, but does not establish the selected E31 authorization in this record. That unanswered point remains unknown. A machine's brand family, reservoir size or a retailer's list of many compatible brands is not a replacement for the actual model requirement. If the source names a different product, resolve the difference rather than treating physical fit as permission.
Use the dimension for a bounded buying question
The geometry is useful when confirming that a seller has supplied the intended E31 variant rather than another tablet. Keep the product code, count and actual label together. If the purchase depends on an equipment fit or approval question, obtain the exact maker answer before use. No cleaning, dissolution or residue experiment has been conducted by this reference, and the calculator cannot turn the specification into one.
Physical clearance cannot answer a chemistry question
A tablet that enters an opening still has an actual formulation, mass and intended application. Conversely, a tablet that looks larger in a photograph has not been physically measured against a machine by this site. Do not interpret either observation as a tested compatibility result. The selected 15 mmspecification is retained so the right product can be identified, not so the website can calculate a safe compartment clearance. If a machine instruction requires a particular tablet, obtain the relevant exact product evidence rather than using a visual size comparison to authorize a substitute.
Sources & scope
Checked November 4, 2026. Manufacturer and retailer references support the specific statements. Dated displayed prices are not final checkout quotes, performance rankings or performance testing. This shopping reference does not replace the exact product label or qualified individual advice. Current received labels, exact chemical/model authorization and independent chemical/equipment/content/commerce review remain pending.
Urnex US: Cafiza E31 12-E31-UX100 ↗
Keep reading
What does the reviewed BES870 booklet distinguish? ↗
What if a seller procedure differs from the manufacturer page? ↗