Sekonic L-308X Flashmate (L-308X-U)

D0 No Radio — No radio at all. It cannot phone home.

The unplug test

There is nothing to unplug. The L-308X-U has no network connection to lose in the first place -- it is a single-AA-battery incident/reflected light meter operated entirely through its own buttons and dial. Its 'cordless' flash-metering mode detects a flash burst optically through the meter's own sensor, not over any radio link. Nothing about it can phone home because it has no radio to do so with.

Why this tier: The L-308X-U is registered under FCC Part 15 Subpart B as an unintentional radiator (Class B verification), which is the opposite of an intentional-radiator grant and directly supports D0. Its own manufacturer spec sheet lists no Wi-Fi, Bluetooth, or any wireless connectivity; its 'cordless flash' metering mode is optical detection of a flash burst through the meter's own sensor, not a radio link of any kind. Operation is entirely physical controls (buttons, dial, single AA battery), with no app and no account anywhere in the product. No intentional radiator, no radio, no vendor cloud: D0.

Specifications

Account required	none
Works offline	fully
Forced firmware updates	no
Radios	none
FCC ID	no intentional-radiator grant found
Local control	none
Phones home	none
Parts available	unknown
Availability	in stock
Price band	unknown
Vendor risk	0 / 3

Where to buy

Open questions

Current US price was not researched, per project budget guidance to leave price unknown rather than spend a search confirming it.
Whether Sekonic's separately-sold wireless light meters (e.g. the L-858D-U, which does integrate a radio flash trigger) share any FCC grantee code with the L-308X was not checked; not needed for this D0 claim, which rests on the L-308X's own Part 15B classification and full spec sheet.

Sources

Class A is primary (manual, FCC filing, teardown). Class B is corroborated community reporting. Class C is never sufficient alone.

A https://global.sekonic.com/sekonic-l-308x-flashmate-light-meter/
Manufacturer's own product page: full feature and specification list (incident/reflected metering, photo/cine/HD-cine modes, PC sync terminal, cordless flash detection, calibration compensation, three custom settings) contains no Wi-Fi, Bluetooth, app, or account of any kind -- purely a physical-control device. — accessed 2026-09-04
B https://www.bhphotovideo.com/c/product/1390250-REG/sekonic_401_305_l_308x_u_flashmate_light_meter.html
Major retailer listing: confirms the device is 'registered as FCC Part 15 Subpart B Class B equipment,' i.e. an unintentional-radiator verification rather than an intentional-radiator grant -- the FCC-heuristic evidence that no radio transmitter is present. Also confirms current in-stock US availability. — accessed 2026-09-04

History

2026-09-04 — First published at D0.

Last verified 2026-09-04 — 2 days ago.