Modular Ø40–Ø60mm LED signal towers are the default 2026 build, with Qlight's STG40L/STG60ML covering Ø40 and Ø60 at 12/24V DC and 110–220V AC, IP54 (buzzer) or IP65 (standard) [S2][S9].
The supply base splits three ways: Japanese majors (PATLITE LA6/LR5/LR6), Korean stack-light specialists (Qlight STG series), and a deep China OEM/ODM tier (Oujie Q1 series, Yinglang Φ55-5001/506) that quotes MOQ 2 pieces and FOB-tier pricing from $6 per unit [S1][S3].
Supplier Tiers and Geographic Spread
PATLITE positions the LA6 (Φ60mm) as a smart-tier device with 21 programmable LED colors, 11 alarm patterns, 85dB output, IP65 (IP54 with alarm), and a built-in web interface, offered in 24V DC plus 100–240V AC variants [S5]. The same vendor's LR6 (60mm) and LR5 (Φ50mm) are distributed by Shikhar Automation and Servodynamics for the South Asian and ASEAN factory-floor channel, with LR5 carrying IP65 and 85dB alarm [S4][S7][S8].
Qlight covers the IO-Link and industrial-network tier with QTG-IOL, QTC-IOL, and QTR-IOL modular towers, alongside classic STG40L (Ø40, 334–559mm height) and STG60ML (Ø60, 106–314mm height) using AS lens, ABS housing, and aluminum pole [S2][S9]. China-based Oujie (Shenzhen) ships the Q1/Q1A series at 30–70mA per color, 15mA buzzer, 1.2–2W, IP53/IP65, with a stated 50,000-hour LED life on a Patch 2835 source [S3]. Yinglang's Φ55-5001/506 series adds a flash mode at 40–60 beats per minute with individually controlled shades and 2–3 colors per module [S1].
Spec Envelope: Diameter, Voltage, IP, and Sound Output
Across the 2026 catalog window, four spec axes dominate RFQ comparison: tower diameter (Ø40, Ø50, Φ55, Ø60mm), supply voltage (12V DC, 24V DC, 110–220V AC, 100–240V AC), ingress protection (IP53, IP54, IP65), and buzzer output (85dB at 1m on PATLITE/Qlight, 95dB on Oujie's 2835-based Q1) [S2][S3][S5][S8]. Diameter choice usually maps to viewing distance: Ø40mm suits workstation cells, Ø50–60mm suits line-level machine status, and any Φ55mm tier (Yinglang) targets mid-line visibility with selectable flash cadence [S1][S7].
Voltage and protocol diverge further. STG40L and STG60ML stick with hard-wired DC/AC only [S2][S9]. LA6 adds USB/Ethernet/PoE configuration plus 24V DC and 100–240V AC M2 variants [S5]. The Qlight smart-factory line layers IO-Link, USB, Ethernet, CAN, and RS485 controlled models (QTG-IOL, QTC-IOL, QTR-IOL, CPK-CAN, CPK-RS4) on top of the same Ø40/Ø50/Ø60 mechanics [S2]. Balluff's SmartLight extends the same concept to 4-series stack lights for fill-level and operator-guidance duty [S10].
Material, Mounting, and Operating-Environment Limits
Lens-housing-pole material sets the environmental ceiling. Qlight specifies AS lens, ABS housing, aluminum pole, with operating range generally quoted at -20°C to +50°C on the LR6 datasheet [S2][S4]. LR5 and LR6 are upright-mount, indoor-only by default, with IP65 on the standard body and IP54 when the buzzer module is fitted [S4][S7][S8].
Oujie's Q1A multilayer warning light lists IP50/IP54 options with 0.5m pre-wired leads and 2835 patch LEDs at 800mcd-class output, targeting automation cells, SMT lines, CNC machine tools, engraving machines, and mining equipment [S3]. Yinglang's Φ55-5001 ships with multiple bracket options to suit horizontal or vertical machine surfaces, and its flash rate of 40–60 BPM is fixed, not programmable, which matters for buyers comparing it against LA6's 11 alarm patterns [S1][S5].
Selection Criteria: Where Each Supplier Wins
For a controls engineer specifying on a greenfield line, the decision tree is short. Pick PATLITE LA6 when you need multi-color programmability, web setup, and global certifications (UL 508, CE EMC, RoHS, FCC, KC), accepting the higher unit cost [S5]. Pick Qlight STG or QTG-IOL when the PLC side already speaks IO-Link or Modbus-TCP and you want the same vendor across 12/24V DC and 110–220V AC variants with IP65 [S2][S9].
Pick a Chinese OEM/ODM (Oujie Q1, Yinglang Φ55) when unit cost, MOQ 2, and 1–3-day sample turnaround matter more than protocol depth, and when 95dB output and 50,000-hour LED life are sufficient [S1][S3]. Pick Balluff SmartLight when the stack light is part of a broader IO-Link sensor family on the same M12 drop [S10]. Maple Systems and Servodynamics act as regional packagers that resell PATLITE LR5/LR6 with local warranty and same-day dispatch rather than as OEM alternatives [S6][S7][S8]. For deeper background on the application duty and how the stack light ties into a wider machine-status spec, the signal tower light sizing and selection guide walks through tier count, color semantics, and PLC I/O budgeting.
Limits, Failure Modes, and What the Datasheets Do Not Say
Three constraints recur across the 2026 lineup. First, indoor-only rating: LR5 and LR6 are explicitly upright, indoor products; outdoor or washdown duty needs a higher IP or a separate weatherproof beacon family [S4][S7][S8]. Second, the 85dB at 1m spec is a free-field rating, so on a noisy shop floor (Oujie cites 70–85dB ambient as the working band that 95dB cuts through) real perceived loudness drops fast, which is why Qlight offers a "buzzer volume controllable" option on STG [S2][S3].
Third, LED lifetime figures (50,000h on Oujie Q1) are typically L70-style marketing numbers tied to room-temperature operation; high-ambient enclosures above +50°C will derate them, and none of the four primary datasheets publishes a TM-21 extrapolation or a lumen-maintenance curve [S3]. Buyers who need hazardous-area duty should note that none of the Ø40–Ø60mm modular towers above carry an ATEX or IECEx marking in the research; Qlight lists an "Explosion Proof Tower Lights" category separately from the STG series, confirming the modular LED stack itself is not the Ex-rated product [S2].
Standards, Compliance, and Documentation
PATLITE LA6 declares conformity to EMC Directive, RoHS Directive, UL 508, FCC, and KC, with UL Recognized Components on 24V types only [S5]. The China-tier Oujie Q1 lists IP53/IP65 (IEC 60529 ingress class) but does not name UL or CE in the catalog excerpt, so EU/US export orders should request the test report before issuing a PO [S3]. Qlight's STG and the smart-factory QTG/QTC/QTR lines ship with certificate downloads, including DoC and KC documents, on the vendor's customer-support portal [S2].
For an industrial buyer, the practical 2026 spec floor is therefore: 24V DC supply, Ø40 or Ø60mm diameter, IP65 body (IP54 if a buzzer is fitted), 85–95dB at 1m, AS/ABS/aluminum construction, and at minimum an EMC + RoHS declaration. Anything below that is a residential-grade product masquerading as industrial; anything above (smart IO-Link, web setup, multi-color) carries a clear cost premium worth paying only when the PLC architecture actually consumes that data, as outlined in the signal tower light sizing and selection guide.
Trackable next signals: vendor release of IO-Link v1.1.4 IODD files for the QTG-IOL family, and a follow-up announcement on a UL-recognized 24V variant of LA6 with extended -30°C to +60°C rating, both of which would shift the 2026 spec floor cited above.
For component-level specifications, see signal tower light, lamps and light fittings, and tower crane.