The Z366-250-A50R is a 3-position 50 mL round-bottom tube insert for the Hermle Z366-250 swing-out bucket on the Z366 / Z366-K chassis 4-place rotor — sold as a 2-pack. Each insert holds 3 × 50 mL round-bottom tubes; the 4-bucket rotor configuration takes 2 packs (4 inserts) for full symmetric loading, delivering 12 × 50 mL round-bottom tubes per cycle in swing-out geometry on the deep cold-chain Z366-K chassis (−2 °C at max speed). Sister insert to the Z366-250-A50 (50 mL Falcon conical) — same 50 mL volume but different tube envelope geometry.
Key Specifications
| SKU | Z366-250-A50R |
| Type | Tube insert — 3 × 50 mL round-bottom |
| Pack quantity | 2 inserts per SKU (full 4-bucket configuration takes 2 units = 4 inserts) |
| Per-insert capacity | 3 × 50 mL round-bottom tubes |
| Per-cycle throughput (full configuration) | 12 × 50 mL round-bottom per cycle |
| Tube format | 50 mL round-bottom glass or polypropylene (29 mm OD, 95–120 mm length range) |
| Compatible bucket | Z366-250 swing-out bucket |
| Compatible rotor | Z366-250 4-place swing-out rotor |
| Compatible chassis | Z366, Z366-K (refrigerated), and -E voltage variants |
| Max. operating speed (with insert + tubes) | Per Z366-250 spec — 4,500 rpm at 3,780 × g maximum |
| Max. radius | 16.7 cm (0.0 cm radius correction — full radius preserved) |
| Temperature at max speed (Z366-K refrigerated) | −2 °C |
| Geometry | Swing-out (0–90°) — flat sediment surface |
| List price | $523 (2-pack) |
Compatibility & When to Order This SKU
Insert pairing — Z366-250 swing-out bucket only. Order this SKU when:
- Adding 50 mL round-bottom workflow to an existing Z366 / Z366-K + Z366-250 install — order 2 units for full 4-bucket symmetric loading (12 tubes/cycle).
- Glass round-bottom 50 mL workflows when the protocol requires glass for organic-solvent compatibility, repeated autoclave reuse, or precise volume measurement.
- Deep cold-chain glass round-bottom 50 mL workflows on the Z366-K refrigerated chassis at near-freezing temperature.
- Replacement inserts if a current set is damaged or worn.
Application Profile
Round-bottom vs conical (vs the A50 sister). The A50R holds 50 mL round-bottom tubes (95–120 mm length range — accommodates short-format and long-format round-bottom variants). The A50 sister insert holds 50 mL Falcon-style conical (116 mm length). The two formats have different shoulder geometries; using the wrong insert risks tube fit problems and balance issues.
Glass tube workflow compatibility. 50 mL round-bottom glass tubes support workflows requiring glass for organic-solvent compatibility, repeated autoclave reuse, or precise volume measurement (graduated glass tubes).
4-bucket symmetric loading. All 4 buckets must use matching A50R inserts for symmetric balance.
Design Architecture
Deep cold-chain glass-compatible 50 mL workflows — organic-extraction, chemical-prep, and precipitation workflows in 50 mL round-bottom glass at near-freezing temperature.
Cold-chain protein prep in glass round-bottom — TCA, ammonium-sulfate, organic-precipitation in 50 mL round-bottom glass on the deep cold-chain swing-out chassis.
Cell-culture prep in 50 mL round-bottom glass — when cell-culture protocols specify round-bottom glass for resuspension volume measurement or solvent-compatibility requirements.
Density-gradient prep in 50 mL round-bottom — Ficoll, Percoll, sucrose-gradient prep where the swing-out flat-sediment geometry preserves gradient interfaces and round-bottom tubes are the protocol format.
Cold-stable analyte preservation workflows — protocols requiring near-freezing temperature stability through the centrifugation step in 50 mL round-bottom format.
Cross-format Z366-K core facilities — labs that run both round-bottom and conical 50 mL workflows benefit from stocking both A50 and A50R inserts on the same bucket.
Ordering & Configuration
4-bucket symmetric loading. All 4 buckets must use matching A50R inserts. Mixed-bucket configurations produce mass asymmetry.
Per-insert symmetric loading. Within each insert, the 3 round-bottom tubes should be balanced symmetrically — pair tubes by mass.
Tube cap confirmation. All round-bottom tubes must be capped securely before spinning at 4,500 rpm.
Z366-250-A50R ships as 2 inserts. 50 mL round-bottom tubes (glass or polypropylene) are operator-supplied. The Z366-250 bucket is sold separately.
Confirm at quote: bucket pairing (Z366-250 in inventory), chassis pairing (Z366 or Z366-K), tube format (50 mL round-bottom; conical uses A50), pack count (2 packs for full 4-bucket configuration), and lead time.
Warranty: 5-Year Hermle warranty (3 years full + 2 years drivetrain) on the inserts.
Z366-250 50 mL insert pair (Z366 / Z366-K chassis):
- Z366-250-A50R (this product) — 3 × 50 mL round-bottom (12/cycle)
- Z366-250-A50 — 3 × 50 mL Falcon-style conical (12/cycle)
Match the insert to the workflow's tube envelope geometry.
