Power that pays for itself.
Sintron engineers smart coin & mobile-payment power boxes, ETL-listed NEMA connectors, and rugged RV power gear — trusted by laundromats, arcades, and workshops across North America.
Four product lines.
One standard of engineering.
From self-service businesses to off-grid adventures — every Sintron product is built around safety, durability, and smart convenience.
Smart Payment Power Boxes
Coin, contactless & mobile-payment timer control boxes for massage chairs, washers, dryers, arcades, and vending — turn any appliance into a self-service business.
View the series →NEMA Plugs & Receptacles
ETL-listed industrial-grade plugs, connectors, and flanged inlets. Heavy duty, DIY-rewirable, rated up to 50A / 12,500W.
View the series →RV & Generator Power
Weatherproof shore power inlets and twist-locking generator connectors for RVs, campers, marine, and home transfer switches.
View the series →Smart Speaker Mounts
Stands and wall mounts for Echo Show, Echo Dot & Google Nest — including our best seller with 6,600+ reviews.
View the series →The Smart Payment Power Box family
ST-001 through ST-005 — from a programmable coin acceptor to LCD power boxes that take Apple Pay, Google Pay, PayPal, Venmo and Cash App.
▶ Watch the full ST-004 introduction
ST-004: the cashless upgrade your business has been waiting for.
One box. Every payment method. The ST-004 accepts coins and contactless payments — Apple Pay, Google Pay, PayPal, Venmo, and Cash App — and meters power by time, so your massage chairs, washers, and dryers earn while you sleep.
- LCD display with programmable time-per-payment settings
- Accepts coins + tap-to-pay mobile wallets — no POS system needed
- Drop-in install for massage chairs, washers, dryers & shoe polishers
- Rugged steel enclosure built for unattended commercial use
See it wired up, paid for, and running.
Setup walkthroughs, feature demos and real installs from our YouTube channel. Every clip plays right here — no need to leave the page.
Shorts from the shop floor
Quick looks at the ST-004 on real washers and dryers.Read the manual before you buy, not after.
Every Sintron payment box ships with a digital manual, and all of them are open on our own site — no sign-up, no PDF download. Check exactly what setup involves before you order.
ST-004 · ST-004-F · ST-005 manual
The full manual for the LCD coin & mobile payment boxes — quick start, coin and timer settings, the setup page, and the FAQ.
Open the manual →ST-002 · ST-003 manual
Everything for the coin-operated timer boxes, including the ST-001 coin acceptor setup and mode settings.
Open the manual →Payment gateway setup
Step-by-step for connecting PayPal, Stripe, Square, Revolut and myPOS so customers can tap to pay.
Open the manual →Setup page reference
Every field on the built-in Wi-Fi setup page explained — pricing, run time, custom LCD text and email alerts.
Open the manual →Firmware update (OTA)
How to pull the latest firmware over the air, and what each release adds to your box.
Open the manual →Which model do I need?
A short guide to picking between the ST-002, ST-003, ST-004 and ST-005 for your voltage, plug type and payment mix.
Open the manual →NEMA plugs, inlets & RV power gear
ETL-listed, industrial-grade, weatherproof. The hardware professionals trust for generators, shore power, and heavy-duty appliances.
Smart speaker stands & wall mounts
Our best-reviewed product line. Adjustable stands for Echo Show, space-saving wall mounts for Echo Dot and Google Nest Mini.
Stand for Echo Show 5 (3rd Gen) — 360° Rotation, Swivel & Tilt, Black
Stand for Echo Show 5 (3rd Gen) — 360° Rotation, Swivel & Tilt, White
Outlet Wall Mount for Google Nest Mini & Home Mini — Cord Management
▶ Watch video2-Pack Outlet Wall Mount for Google Nest Mini & Home Mini
▶ Watch videoBuilt like infrastructure.
Designed like a product.
ETL Listed Safety
Independently tested and certified to North American electrical safety standards.
Cashless-Ready
Apple Pay, Google Pay, PayPal, Venmo & Cash App support — no extra POS hardware.
Industrial Grade
Heavy-duty enclosures and connectors rated up to 50A / 12,500W for real-world abuse.
Fulfilled by Amazon
Fast Prime delivery, easy returns, and verified customer reviews on every product.
Watch it work, then read the reviews on Amazon
Every rating and review for our products lives on Amazon, where it is collected and verified by Amazon — not reproduced here.
▶ Our most-watched video on YouTube
Read verified reviews
Ratings on our product cards are copied from our Amazon listings. Open any product to read the full, Amazon-verified reviews behind those numbers.
Browse the Amazon storefront →Questions before you buy?
Our YouTube channel has setup walkthroughs, wiring guides and troubleshooting for the ST-series payment boxes and our speaker mounts.
Watch the tutorials →Ready to power your next project?
Browse the full Sintron catalog on Amazon — Prime shipping, verified reviews, and brand-direct support.
Shop the Amazon Storefront →