KOKEN LTD.
Koken BL-321 Series Bresslink

Manufacturer: KOKEN LTD.
Model: BL-321 Series
Lightweight performance in a cordless design
Sakai Model BL-321 Series
A Powered Air-Purifying Respirator (PAPR) that minimizes leakage risks, ensuring safety while reducing the physical burden on the user through a lightweight facepiece design integrated with a motor and battery.
The BL-321 series utilizes “Breath-Link” technology to synchronize airflow with the user’s breathing rhythm, reducing fatigue and conserving battery power during use. This is a lightweight, cordless series featuring a compact battery, delivering both comfort and safety.
Lightest weight in the domestic market※
Enhanced water resistance
Replaceable filters (PL1/PL3 classifications)
※The BL-321S is a Japanese domestic PAPR product, released in May 2018 (according to company research).

Sakai Model BL-321S-02
Powered Air-Purifying Respirator
Uses BLA-62 Filter
Particle Collection Efficiency: 95.0% or higher (PL1)

Sakai Model BL-321H-02
Powered Air-Purifying Respirator
Uses BRD-82 Filter
Particle Collection Efficiency: 99.97% or higher (PL3)
| One device suited for multiple operations! | ||||
|---|---|---|---|---|
| Metal grinding and general dust | Welding operations | Tunnel construction | Asbestos removal | Indium handling operations |
![]() | ![]() | ![]() | ![]() (BL-321H model only) | ![]() (BL-321H model only) |
Easier to use with Breath-Link Technology
Breath-Link technology, featuring a unique blower structure (BSFS), implements “silent blowing” during inhalation and stops blowing during exhalation, minimizing fatigue when wearing the respirator. By utilizing a cordless electric fan, this product reduces power consumption while achieving a significantly lighter weight compared to conventional devices.
- Lightweight
Improved fan efficiency reduces battery power consumption, allowing for a smaller battery and greater mobility. - Easy Breathing
Synchronized airflow matches your breathing rhythm, reducing the discomfort often associated with wearing masks. - Reduced Operating Costs
Precise control of fan rotation speed conserves energy and lowers long-term operating costs.
Airflow Warning System for Safe Operation
To maintain the safety of a Powered Air-Purifying Respirator, it is crucial to sustain adequate airflow and keep the internal facepiece pressure positive.
The BL-321 notifies the user via an “airflow alert” if the internal pressure drops due to filter clogging or battery depletion, which causes a reduction in airflow.

The system maintains stable internal pressure until a filter replacement is required.
- Filter clogs → Airflow decreases → Internal pressure drops → Constant airflow warning triggered
- Battery consumption notification → Low battery alert triggered
Rhythmic airflow helps regulate pressure and minimizes energy consumption.
Performance and Specifications
| Model Name (Product Code) | Sakai Model BL-321S-02 | Sakai Model BL-321H-02 | |
|---|---|---|---|
| National Assay Certificate | No. TP100 | No. TP101 | |
| Applicable Filter | Alpha Ring Filter BLA-62 | Alpha Ring Filter BRD-82 | |
| Head Harness | SBW/SAW Type | ||
| Classification | Fan Performance | High Airflow Type | |
| Inward Leakage Performance | Class B (Below 5.0%) | Class S (Below 0.1%) | |
| Filter Material Performance | PL1 (95.0% or higher) | PL3 (99.97% or higher) | |
| Rated Operating Time※1 | Approx. 3.5 hours | Approx. 3 hours | |
| Actual Operating Time※2 | Approx. 5 ~ 9 hours | Approx. 3 ~ 6 hours | |
| Weight | Under 252g (Avg. 245g) | Under 265g (Avg. 257g) | |
| Battery | Dedicated Rechargeable Lithium-ion Battery (Rated Voltage: 3.7V – Rated Capacity: 1100mAh) | ||
| Recharge Cycles | Approx. 300 cycles※3 | ||
| Charging Time | Approx. 3 hours※3 | ||
| Electric Fan Durability | Approx. 2,000 hours※3 | ||
※1 The duration positive pressure is maintained inside the mask under high airflow breathing conditions in a standard room (National Assay Standard).
※2 The duration positive pressure is maintained inside the mask in a dusty environment, based on actual worker breathing data during operations.
※3 May be shorter depending on usage conditions.
Water-Resistant Design Prevents Ingress ※1
Further improved water resistance necessary for actual field work, achieving an IP55 dust and water resistance rating ※2. Designed to protect against dust and water jets. Can be used during sudden rain or in operations involving water splashing.
Notes:
- ※1: Water resistance is not guaranteed in all usage situations.
- ※2: Complies with JIS C0920 standard for degrees of protection provided by enclosures (IP Code).
Maintenance
Adhered dust can be cleaned off with running water.
For stubborn dirt that cannot be wiped away, the unit can be cleaned by washing it with water. ※
Notes:
- ※: Be sure to use the maintenance plug (sold separately) during washing.
- ※: Do not submerge the unit in a bucket or spray water into the inside of the mask.
- ※: The battery and filters cannot be washed with water.

Battery Drop Prevention
The battery is secured by a “Release Lever” inside the battery case to prevent it from falling out.

Other Features:
- Failsafe Protection
Even if the battery is removed or depleted, the mask maintains particulate protection equivalent to a standard non-powered dust respirator. - Auto ON/OFF Function
The fan automatically starts when the mask is donned and the user inhales, and it automatically stops when the mask is removed. - Silicone Material
Utilizes silicone material for a comfortable and durable skin seal. - SBW/SAW Type Harness
Uses SBW/SAW type harnesses for high durability and stress resistance. - Speaking Diaphragm
Equipped with a built-in voice transmitter to allow communication and instructions while wearing the mask.
Disclaimer:
- The color of the product may differ from the actual color due to printing or photography lighting.
- Product specifications and designs are subject to change without prior notice for improvement purposes.
















