The ER-SB40 runs a linear motor at 9,800 cuts per minute behind a dial that steps through 19 lengths from 0.5mm to 10mm. GQ found it clears thick growth quickly with few pulls and rates it a strong tool for short beards and stubble, but a large one, awkward to steer around a jawline and heavy in a wash bag. It is waterproof and runs 60 minutes off a charge.
Full review
9,800 cuts per minute through dense growth
The linear motor holds its speed as hair thickens rather than bogging down, which is what stops a trimmer from pulling instead of cutting. GQ described the result as clearing unwanted hair quickly with surprisingly few nicks and pulls, and credited the hypoallergenic stainless blades with keeping irritation low. Wide, rounded blade tips take more hair per pass, so fewer passes are needed.
19 settings from 0.5mm to 10mm on one dial
A dial on the handle steps through 19 lengths in 0.5mm increments, and it turns mid-shave without swapping combs. GQ singled out being able to experiment on the fly as what makes the trimmer low-effort to use. Taking the comb off entirely leaves a cut of about 0.5mm. The ceiling is 10mm, which is short for anyone maintaining a longer beard.
Sealed for the shower, rinsed under the tap
The body is waterproof, so it runs cordless in the shower and washes out under a running tap afterwards. That is the practical difference between this and a trimmer that has to be brushed out over a sink and never quite comes clean. A charge takes an hour and lasts 60 minutes, and a five-minute top-up buys a couple of minutes of trimming.
Too big to steer around a jawline
GQ's main complaint is size: a large gadget to hold, to store and to pack, and unwieldy enough around the jawline that early attempts needed careful wrist work to avoid taking off more than intended. The crosshatched grip and flat base help on a countertop. In an overnight bag the weight is noticeable in a way a smaller trimmer's is not.
A battery gauge with three states
The indicator shows full, mid or low and nothing in between, which GQ found unhelpful when time was short before work. There is no minutes-remaining readout and no warning before the charge runs out mid-trim. On a trimmer at this price that is a cheap-feeling omission rather than a serious fault.
Strengths
- +High-performance linear motor delivers 9,800 cuts per minute for efficient trimming of thick, dense hair
- +19 precision length settings (0.5MM to 10MM) with quick-adjust dial for customizable styling
- +Ergonomic rubberized grip provides better control during use
- +Waterproof design allows for cordless trimming in the shower and easy cleaning
Watch-outs
- −Large and heavy, awkward around the jawline and noticeable in a travel bag
- −The battery gauge shows only full, mid or low, with no minutes-remaining readout
- −A 10mm ceiling is too short for anyone growing a beard out
- −60 minutes of runtime per charge is modest for the price
How it compares
More motor than the Philips Norelco 3000 Series and properly waterproof with it, which is what justifies the price gap. The Wahl Groomsman runs longer between charges and is far easier to travel with. Above 10mm this stops being the right tool for the job.
Rating sources
“For tidying up shorter beards, Panasonic's super-charged ER-SB40 is best in class.”
“this isn't very specifically a shaving razor but that was what I bought it for I know that there's some really high-tech ones but sometimes you don't need to go high-tech to get what you want”
“If you're rocking anything from heavy stubble up to a full lumberjack beard, the Panasonic ERGB86 is built to handle it.”
Our 4.0 score is the average of these published ratings. Ratings marked * were derived from the reviewer’s written analysis or video transcript — the publisher didn’t print an explicit numeric score, so we inferred one from their own words. Click through to verify. More about methodology.
