MARATHON AirTurbo AT300 REPLACEMENT Bearing — Lab High-Speed Handpiece Service Part

SKU 101574 · MFG #880-3020 · Fits AT300A and AT300W · MARATHON AirTurbo

A REPLACEMENT bearing for the MARATHON AirTurbo AT300 laboratory high-speed handpiece. The AirTurbo is a bench air turbine built for zirconia and all Other ceramics; its casing carries a protection mechanism that keeps grinding debris out of the head, which is what gives the turbine its service life. The bearing is the wear item inside that head — when a turbine starts to whine, lose speed, run hot or vibrate, the bearing is the first thing to check and the cheapest thing to change.

Replacing a bearing at the first sign of noise is the difference between a $36.25 part and a new handpiece. This is a service part sold on its own, not a complete turbine cartridge — if your head is scored or the impeller is damaged, you want the cartridge (#880-1301) instead.

Specifications

Part: REPLACEMENT bearing, MFG #880-3020
Fits: MARATHON AirTurbo AT300 series lab high-speed handpiece — air (AT300A) and air+water (AT300W)
Sold as: 1 pack
Type: service / wear part — no electrical or motor components

Host handpiece specification, published by the manufacturer (Meta Dental Corp) for the unit this part serves — not the specification of the bearing itself:

Maximum speed: 320,000 RPM
Operating pressure: 2.0–2.5 bar (AT300A) / 2.5–3.0 bar (AT300W)
Air consumption: 40 L/min
Bur shank: 1.60 mm (FG)
Handpiece weight: 60 g (air) / 85 g (air + water)

What You Get

One (1) REPLACEMENT bearing pack for the AirTurbo AT300, MFG #880-3020

Not sure this is the part you need? Bearings, cartridges and collet chucks all live inside the same head and are easy to confuse. Tell us your unit (AT300A or AT300W) and what it is doing — noise, heat, loss of speed, bur slipping — and we will confirm the right part before you order. Use Talk to an Expert above.

Works With — the AirTurbo AT300 system

AT300A Air Turbo Lab High-Speed System — complete unit · #AT300A
AT300A Handpiece only · #880-1304
AT300A Cartridge (turbine) for the air high-speed handpiece · #880-1301
Air Turbo Collet Chuck · #880-1303
Air Turbo Collet Chuck · #880-3030
Air Turbo Regulator · #880-1302
Air Turbo Water Control Box / Regulator · #880-2302
AirTurbo Tool Kit · #880-3040
AirTurbo Foot Pedal · #880-3500

A bur that slips points to the collet chuck. A head that is scored or will not hold speed after a bearing change points to the cartridge. Low or unstable pressure at the handpiece points to the regulator.

Documentation

Meta Dental Corp publishes specifications for the AirTurbo AT300 handpiece but does not publish a separate printable data sheet, IFU or exploded PARTS diagram for this service part, so none is linked here rather than link a document that is not theirs. The host handpiece figures above are quoted from the manufacturer. If you need a stamped PARTS diagram for a service record or a warranty claim, ask us and we will request one from the factory.

AUTHORIZED DISTRIBUTOR

US DENTAL DEPOT
US Dental Depot is an Authorized MARATHON Distributor. Every MARATHON item we sell is genuine, factory-fresh stock sourced through authorized channels and shipped from our own facility in Boca Raton, Florida, with US-based support.

WARRANTY & GUARANTEE

US Dental Depot warrants this product for 1 year from the date of purchase against manufacturing defects in materials and workmanship. Normal wear and ordinary consumption through use are excluded. A bearing is a wear part and will consume with normal use; this covers manufacturing faults, not service life. If an item arrives defective or fails from a manufacturing fault, we replace it.

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Product description last updated: July 25, 2026