The Z366-250-B57 is a direct-fit bucket dimensioned for 14 × 1.8–7 mL Vacutainer-style pediatric blood tubes — sized for the Hermle Z366-250-HC swing-out rotor on the Z366 / Z366-K chassis 4-place configuration, sold as a 2-pack. Distinct from the bucket-plus-insert approach (Z366-250 + Z366-250-A57 insert delivers 56 × 1.8–7 mL Vacutainer per cycle), the B57 direct-fit bucket on the HC rotor variant delivers the same per-cycle throughput (56 tubes) but with a dedicated bucket geometry purpose-built for small-volume Vacutainer workflows. Pick the B57 when the workflow is dedicated to pediatric / small-volume clinical blood-component prep on the cold-chain HC platform.
Key Specifications
| SKU | Z366-250-B57 |
| Type | Direct-fit bucket — 14 × 1.8–7 mL Vacutainer-style |
| Pack quantity | 2 buckets per SKU (full 4-bucket configuration takes 2 units = 4 buckets) |
| Per-bucket capacity | 14 × 1.8–7 mL Vacutainer-style tubes |
| Per-cycle throughput (full configuration) | 56 × 1.8–7 mL Vacutainer tubes per cycle |
| Tube format | 1.8 mL, 5 mL, or 7 mL clinical Vacutainer-style (~13 mm OD, 75–100 mm length) |
| Compatible rotor | Z366-250-HC swing-out rotor (HC = high-capacity variant of Z366-250) |
| Compatible chassis | Z366, Z366-K (refrigerated), and -E voltage variants |
| Max. operating speed | 4,500 rpm at 3,735 × g maximum |
| Max. radius | 16.5 cm (0.5 cm radius correction with this bucket) |
| Temperature at max speed (Z366-K refrigerated) | −2 °C |
| Geometry | Swing-out (0–90°) — flat sediment surface |
| List price | $534 (2-pack) |
Direct-Fit Bucket vs Bucket-Plus-Insert — Configuration Choice
The Z366 chassis offers two paths for swing-out small-volume Vacutainer workflows:
| Configuration | Per cycle | Approach |
| Z366-250-B57 (this SKU) | 56 × 1.8–7 mL Vacutainer | Direct-fit bucket on Z366-250-HC rotor (dedicated to small-volume Vacutainer) |
| Z366-250 + Z366-250-A57 insert | 56 × 1.8–7 mL Vacutainer | Bucket + insert on Z366-250 rotor (bucket holds other inserts too) |
Per-cycle throughput is the same; the choice depends on whether the lab needs the bucket to serve multiple formats (insert path) or dedicate to small-volume Vacutainer only (direct-fit path). Direct-fit buckets typically have slightly lower acquisition cost per workflow when the workflow is single-format-dominant.
Compatibility & When to Order This SKU
Bucket pairing — Z366-250-HC rotor only. Order this SKU when:
- Commissioning a Z366-250-HC for institutional pediatric / small-volume clinical-blood workflow — order 2 units for full 4-bucket configuration (56 tubes/cycle).
- Adding pediatric / small-volume Vacutainer capability to an existing Z366 / Z366-K install with the HC rotor variant.
- Workflows dedicated to small-volume Vacutainer format — when the bucket doesn't need to serve other tube/bottle formats.
- Replacement buckets if a current set is damaged or worn.
Application Profile
Institutional pediatric clinical-blood-component prep at 56 tubes per cycle — hospital pediatric labs and pediatric reference labs that batch institutional volume of pediatric samples per cycle for serum/plasma separation.
Pediatric infectious-disease cohort prep — pediatric infectious-disease research (pediatric HIV, pediatric TB, pediatric respiratory pathogen studies) where many pediatric samples need cold-chain processing on the deep cold-chain chassis.
Deep cold-chain small-volume clinical-research recruitment — recruiting-phase studies that draw 5 mL or 7 mL collection tubes at high per-day volume on the deep cold-chain HC chassis.
Veterinary clinical at scale — small-animal blood-component separation in 5/7 mL tube formats at institutional veterinary practice or veterinary-research lab throughput.
Hospital reference labs handling pediatric specimens at scale — pediatric clinical chemistry and hematology prep at institutional throughput on the dedicated bucket configuration.
Cross-format Z366-K / HC core facilities — labs that have a dominant pediatric / small-volume workflow can dedicate the HC rotor + B57 buckets to that workflow while running the standard Z366-250 + bucket-insert configuration for other formats.
Ordering & Configuration
4-bucket symmetric loading. All 4 buckets must be installed for symmetric balance at 4,500 rpm.
Per-bucket symmetric loading. Within each bucket, the 14 tubes should be balanced symmetrically. Mixed 1.8/5/7 mL runs require pre-balance by total tube + sample mass.
Tube cap confirmation. All Vacutainer rubber stoppers must be fully seated before spinning at 4,500 rpm.
Z366-250-B57 ships as 2 buckets. 1.8/5/7 mL Vacutainer-style tubes are operator-supplied (commodity clinical phlebotomy supplies).
Required for operation:
- Z366-250-HC rotor body (sold separately) or already in inventory
- For full 4-bucket configuration: order 2 units of this SKU
Confirm at quote: rotor pairing (Z366-250-HC in inventory), chassis pairing (Z366 or Z366-K), tube format (1.8/5/7 mL Vacutainer-style), workflow drivers (deep cold-chain, pediatric protocol, dedicated bucket vs bucket-insert flexibility), 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 buckets.
Z366-250 small-volume blood-tube workflow paths (Z366 / Z366-K chassis):
- Z366-250-B57 (this product) — direct-fit bucket on Z366-250-HC, 56 tubes/cycle (dedicated to small-volume Vacutainer)
- Z366-250-A57 — insert on Z366-250 bucket, 56 tubes/cycle (bucket-insert flexibility for multiple formats)
Pick B57 when small-volume Vacutainer is the dominant or sole workflow on the chassis; pick A57 when the bucket needs to serve multiple tube/bottle formats.
