By Lin · How we pick · Full Fit Finder
This is the largest family in home espresso, and it contains the most expensive misunderstanding in it. The machines are described as 54 mm and the aftermarket is full of 54 mm tampers — but the stock baskets are tapered, so the bore narrows toward the base. A true 54 mm tamper binds on the wall before it ever reaches the coffee. The number you want is 53.3 mm.

| Part | Size | Why it matters | |
|---|---|---|---|
| Portafilter | 54 mm | Bottomless (naked) portafilters for this family are 54 mm. A bottomless basket shows channelling you cannot see otherwise. | Check price ↗ |
| Filter baskets | 54 mm | Stock sizes run roughly single 8–11 g, double 16–18 g, triple 18–22 g. Precision baskets (IMS, VST) are made in 54 mm for this family. | Check price ↗ |
| Tamper — stock basket | 53.3 mm | ★ The single most common mistake. Stock Breville baskets have slightly tapered walls, so a 53.3 mm tamper is the correct fit — not 54 mm. | Check price ↗ |
| Tamper — precision basket | 54.0 mm | Precision baskets have straight walls, so they take a true 54.0 mm tamper. Note that some brands also sell 54.3 mm in this family — that extra third of a millimetre is enough to catch on the wall in some basket and tamper combinations, so 54.0 mm is the safer default unless a maker states otherwise for your exact basket. | Check price ↗ |
| Dosing funnel | 54 mm | Magnetic funnels sit on the portafilter rim. On machines with a built-in grinder, check it still clears the auto-dose cradle. | Check price ↗ |
| Puck screen | 53.3 mm | Sits on top of the puck. Sized slightly under the basket so it drops in — 53.3 mm, not 54 mm. | Check price ↗ |
| Distribution / leveller | 53–53.3 mm | Levels the grounds before tamping. Same tapered-wall logic as the tamper. | Check price ↗ |
| WDT tool | Universal | Needles stir the grounds to break clumps. Not size-specific — any WDT works. | Check price ↗ |
| Knock box | Universal | Not size-specific. | Check price ↗ |
| Scale | Check clearance | Any timer scale works, but the Bambino/Bambino Plus drip tray is shallow — a slim scale fits better under the spout. | Check price ↗ |
Accessories are shared across this whole family. Anything sold for the Barista Express, Barista Pro or Bambino will fit the Bambino Plus, and vice versa.
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