Blood Pressure Monitor

Blood Pressure Monitor

Model CK-A138 Auto Arm Style Blood Pressure Monitor

Pressure measurement range: 0 mmHg up to approximately 299 mmHg.

Pulse rate range: roughly 40 to 199 beats per minute.

Accuracy listed as 3 mmHg for blood pressure and 5% for pulse rate.

Physical & cuff specs

Size: roughly 135.5 × 93.5 × 60.5 mm (Main unit) according to one source.
Weight: approx. 248g in one spec sheet.

Arm cuff circumference (in one version): 22 cm-32 cm ( 8.7 to 12.6 ) for the standard cuff.


Power: 4 × AA batteries (some sources) or equivalent; automatic power-off is included.

Memory: Storage for past measurements - one spec says "90 sets" of measurement data memory.

Additional Features

Large LCD display for easier reading.

Low battery indicator, cuff detection/alert for incorrect placement may be present in some versions.

Intended for home use (and per FDA submission also authorised for hospital/home).

Strengths & What It Does Well
Good core accuracy specs: 3 mmHg is competitive in many home-use automatic monitors.

Clear display & user-friendly physical size: The size and readability make it suitable for regular home checks.

Simple operation: With automatic inflation/deflation and memory storage, it's designed for ease of use rather than clinical complexity.

Approved/supported for home use: Per the FDA submission for this model (CK-A138) and related models, it meets safety and performance standards (e.g., ISO/AAMI 81060-2) for non-invasive upper arm monitors.
Reasonable cuff range for average adults: Covers typical upper-arm sizes (22-32 cm) in standard form.

Considerations & Potential Limitations
Cuff size may be limiting: If your upper arm is larger than ~32 cm ( 12.6 ) you may need a larger cuff model or variant. Some listings indicate wider range (22-42 cm) but this may be a different version/branding.


User setup/reading technique still matters: As with any BP monitor, incorrect cuff placement, posture, or movement can impact accuracy.

Memory and multi-user features: Though memory exists, some users might want more extensive logging, multiple user profiles, or cloud sync. This model may not have all that.

How to Use It for Best Results
To maximise accuracy and reliability:

Sit quietly for 5 minutes before measuring; keep your arm at heart level, feet flat on the floor.

Wrap the cuff snugly around the upper arm, about 2 cm (approx. one finger width) above the elbow crease.

Avoid heavy meals, caffeine, smoking, exercise for at least 30 minutes before measurement.

Take readings at same time each day (morning and/or evening) for trend-tracking.

Record the readings and share with your healthcare provider if you're tracking hypertension or other issues.

Ensure batteries are sufficiently charged and that the cuff is properly attached every time.

Be aware that even good home monitors have some margin of error; consider having it compared with a clinic reading occasionally.

Summary Verdict
The CK-A138 blood pressure monitor offers a very capable, straightforward upper-arm automatic blood pressure machine with competitive accuracy specs for home use. If you're looking for a reliable device to monitor your blood pressure trends at home without needing all the advanced smart features, it's a solid choice.

What's in the box
1 x Blood Pressure Monitor
1 x Arm Cuff to Wrap Around the Arm.
1 x Instruction Manual