FSC FS-BTSLP01-CG
A discontinued sleep-oriented Bluetooth 5.0 neckband earphone in camouflage green. Retailer-listed specs indicate ~10 h playback, ~2 h charge via micro-USB, 20 g mass, and sales end in Japan. With no public third-party acoustic measurements, we evaluate scientific validity from a neutral baseline and confirm cheaper, measured alternatives exist.
Overview
FS-BTSLP01-CG is a compact neckband Bluetooth earphone marketed for side-sleep comfort. Retailer-listed specifications state Bluetooth 5.0, codec support (SBC/AAC/aptX/LDAC), approximately 10 hours playback, ~2 hours charging over micro-USB, and 20 g weight. The listing also marks the item as sales ended with a last observed price of 2,980円, used here as the basis for a 20 USD denominator via same-day official conversion. These are catalog (retailer) specs; no official product page with detailed measurements was located as of this date [1].
Scientific Validity
\[\Large \text{0.5}\]No independent lab measurements (frequency response, THD, S/N, isolation, ANC) were found for this model. In line with a measurement-first stance, we take a neutral baseline when performance is unknown and limit claims to catalog facts (Bluetooth 5.0, codecs, battery/charging) clearly labeled as retailer-provided [1]. Until controlled data appears, scientific conclusions about fidelity cannot be drawn beyond functionality confirmation.
Technology Level
\[\Large \text{0.2}\]The platform appears commodity-grade: Bluetooth 5.0, micro-USB charging, no documented app-based tuning, no ANC, and no advertised adaptive features. Absent verifiable engineering differentiators or published acoustic design data, technological sophistication is judged low from a 2025 perspective [1].
Cost-Performance
\[\Large \text{1.0}\]Cheapest equal-or-better comparator: JLab GO Air POP. It provides equivalent user functions (stereo Bluetooth playback with integrated mic) and has public third-party measurements documenting performance, e.g., treble accuracy standard error 3.46 dB and comprehensive isolation/latency results [2]. A widely available US retail price of 19.99 USD is confirmed at Best Buy [3].
Calculation (USD basis): 19.99 USD ÷ 20 USD = 1.00 → 1.0 (rounded to one decimal). Because an equal-or-better, essentially equally priced measured alternative exists, CP rounds to 1.0 while the body discloses the underlying division.
Reliability & Support
\[\Large \text{0.2}\]The product is confirmed discontinued at the retailer listing, and no official support/firmware pathway specific to this model could be located. With sales ended and no documented updates or warranty framework for this SKU, long-term serviceability is uncertain, warranting a low score grounded solely in objective availability facts [1].
Rationality of Design Philosophy
\[\Large \text{0.3}\]Pursuing side-sleep comfort is a coherent use-case, but without controlled acoustic evidence or measurable transparency-improving features (e.g., ANC performance, verified tuning targets), the approach reads as cost-driven commodity execution rather than a measurement-anchored design program. No non-scientific claims were identified; thus the score reflects limited evidence of engineering aimed at audible transparency.
Advice
We do not recommend seeking this discontinued model. If you need a compact, inexpensive option for light, in-bed listening, the JLab GO Air POP offers similar functions plus publicly documented lab data at 19.99 USD in the US market [2][3]. For purpose-built sleep use, consider current low-profile “sleep earbuds” that publish engineering details and maintain active support, noting higher pricing.
References
[1] Yodobashi Camera (JA), “FSC 寝ながらBluetoothイヤホン 迷彩グリーン FS-BTSLP01-CG,” https://www.yodobashi.com/product/100000001005433855/ , accessed 2025-08-20. Catalog (retailer) specs: Bluetooth 5.0, SBC/AAC/aptX/LDAC, ~10 h playback, ~2 h charge, micro-USB, 20 g; marked sales ended and last price 2,980円.
[2] Rtings, “JLab Audio GO Air POP True Wireless — Review,” https://www.rtings.com/headphones/reviews/jlab-audio/go-air-pop-true-wireless , published 2024-09-25, accessed 2025-08-20. Includes measured frequency response accuracy (e.g., treble accuracy std. err. 3.46 dB) and isolation/latency metrics under controlled conditions.
[3] Best Buy, “JLab — GO Air POP True Wireless In-Ear Headphones — Black,” https://www.bestbuy.com/site/jlab-go-air-pop-true-wireless-in-ear-headphones-black/6472667.p , accessed 2025-08-20. Confirms 19.99 USD current market price in the US.
(2025.8.21)