DISTRIBUTOR-FIRST SUPPLY PARTNER · SINCE 1999 BRAND · STC
Economy directional control, no-compromise form factor.
Direct. Reliable. Affordable.
STC (Sizto Tech Corporation) is a California-based pneumatics supplier with US engineering and quality management operations headquartered in Silicon Valley and manufacturing partnerships in Taiwan and China. Operating since at least 2001, STC focuses on economy-tier solenoid valves, air cylinders, regulators, and push-in fittings — products engineered to standard port patterns and widely adopted footprints so they serve the MRO replacement and price-sensitive OEM market without tooling or mounting changes.
The 4V series directional control valves follow the dominant 4-way 5-port pattern found on the majority of plant-floor pneumatic circuits, covering 1/8" through 1/2" body sizes with single-solenoid, double-solenoid, and 5/3 center-condition variants. Voltage options span 12/24 VDC and 24/110/220 VAC with DIN or grommet connectors, so a replacement can match the existing wiring without adapter changes.
STC operates ISO-certified design and manufacturing facilities and positions its line for applications where a standard-footprint, competitively priced directional valve meets the specification — without the premium of a tier-one brand name.
STC is a direct-sourced line for SPC, which means competitive pricing and no middleman markup — right-sized for MRO budgets and price-sensitive OEM jobs.
SPC stocks and sells the 4V series specifically as a like-for-like replacement path for the dominant 4V port pattern.
STC directional valves sit alongside SPC's broader line of FRLs, cylinders, fittings, and tubing, so a full pneumatic circuit can be sourced from one distributor contact.
General Manufacturing → Economy directional valve replacement for plant-floor MRO across light and medium manufacturing. 
Packaging & Printing → Directional control on form-fill-seal and conveyance pneumatics where valve cost is a line-item concern. 
Material Handling & Conveyors → Solenoid valve replacement on pneumatic actuators in sortation and conveyor systems. 
Automotive Manufacturing → Price-competitive valve replacement on body-shop and assembly tooling fixtures. 5/2 single-solenoid spring-return for one-directional actuation with spring return; 5/2 double-solenoid air-return for bi-directional memory; 5/3 center-condition (4V430 series) where the cylinder must hold, exhaust, or pressurize in the de-energized center state.
Match the existing machine wiring: 12 or 24 VDC, or 24/110/220 VAC coil. DIN connector for field-wired installations; grommet connector for pre-wired or panel-mounted applications.
If the existing valve uses the standard 4V port and sub-base pattern, the STC 4V series is a drop-in fit. Confirm body size (100/200/300/400 series maps to 1/8", 1/4", 3/8", 1/2" port) and center condition before ordering.
Tell us the spec and the account and we will come back with the right line, sourced through the distribution network.
—. We reply within one business day with pricing, lead-time, and configured parts.