The 3 types · side-by-side
Distributor-facing reading. Each row gives best-for, key trade-off, capacity, price band, and how many of SPC's tier slots carry an option at that product type.
Product type
Best for
Key trade-off
Typical capacity
Price band
Brands SPC carries
Speed Controller Cylinder-port mount · meter-out (default) or meter-in
Two per double-acting cylinder — non-negotiable.Every double-acting cylinder on every machine. Meter-out throttle points away from the cylinder, restricting exhaust while supply flows free — gives smooth, load-stable motion across the stroke. Meter-in only for single-acting (spring-return) or constant-load cases. Threads directly into the cylinder port.
Pressure-throttling is the wrong fixReducing regulator pressure to slow a cylinder cuts force, not speed — cylinder stalls under load and creeps when load drops. Speed = flow at exhaust, not pressure at supply. Meter-in on a double-acting cylinder produces lurching, load-dependent motion.
4 – 16 mm · 1/4" – 1/2" tube
male connector · elbow · panel mount
male connector · elbow · panel mount
$
1 / 5 · Sang-A only
Flow Control Valve Inline needle valve · bi-directional metering · no check
Line balancing, pilot throttling, sub-circuit trim.Balancing two parallel branches drawing from one supply. Slowing a pilot signal so a sequenced motion doesn't fire early. Trimming the feed to a low-demand sub-circuit. The right tool for general line metering — NOT for cylinder speed (that's a speed controller).
~1/3 of RFQs are actually speed controllersCustomers ask for "a flow control" when they mean a speed controller. The distinction is the integral check: speed controller meters one direction and free-flows the other (what cylinder speed needs); flow control meters both equally (what lines need). Pivot the quote when the application is a cylinder.
4 – 16 mm · 1/4" – 1/2" tube
inline · knurled-knob adjustment
inline · knurled-knob adjustment
$
1 / 5 · Sang-A only
Check Valve One-way functional fitting · load hold, backflow, logic
Load-holding on every cylinder that holds a load.Two pilot-operated check valves at every lift, clamp, and indexing cylinder — traps air on both sides of the piston if supply pressure is lost, locks the rod where it was. Standard inline checks on shared-supply branches prevent backflow causing unintended motion on adjacent cylinders.
Pilot plumbing direction mattersPilot-operated check valves at cylinder ports; pilot line connects to the OPPOSITE cylinder chamber so the check releases on the commanded stroke. Wrong-direction install means the check never releases and the cylinder locks. Arrow on body indicates flow direction; reversed install is the #1 field miss.
4 – 16 mm · 1/4" – 1/2" tube
inline · elbow · push-to-connect bodies
inline · elbow · push-to-connect bodies
$
1 / 5 · Sang-A only
Reading the brand bench column — the bar shows how many of SPC's tier slots (Industry Leader · Emerging · Economical · adjacent) carry an option at that product type. Sang-A owns the functional-fitting half of Motion Control — check valve, flow control, speed controller — at the per-cylinder volumes the customer actually consumes; a narrow bench here means the comparison stops being a tier choice and becomes a single trusted source priced for consumable volume.