About RKI | RKI

Who We Are

RKI is partnered with Riken Keiki Company, Ltd., the world leader in gas detection and sensor technologies.

A Letter from our Founder

Dear Customer,

RKI Instruments, Inc. is an innovative gas detection company located in Union City, California. RKI was established in 1994 by Bob Pellissier and Sandra Gallagher with the belief that customers and distributors deserve a reliable source for advanced gas detection equipment as well as solutions to specific gas monitoring applications.

RKI is partnered with Riken Keiki Co. Ltd., the world leader in gas detection and sensor technologies. In business for over 80 years, Riken has sold over 1,800,000 portable and fixed gas monitors worldwide with annual sales exceeding $220 million. They have over 700 employees, a large number of which are engineers and scientists. RKI is the exclusive North American supplier of Riken products.

Every year, RKI has continued to achieve a high level of growth which is attributed to our sales and support of Riken products and the ability to develop our own line of products around Riken’s long lasting sensors. This capability of sales, support, and development is made possible by our seasoned professionals. Each RKI employee has an average of 14 years of gas detection experience, and the top 8 executives combined industry experience totals over 240 years.

This combination of quality products and knowledgeable supportive people provides you with the ability and opportunity to confidently face almost any gas monitoring application, with equipment built to last. When you call RKI, you will get solutions and answers to your gas detection needs. RKI is ISO 9001 certified.

RKI provides Gas Detection for Life. Not only will our equipment protect your life and property from the hazards of gases and vapors, but with proper care, it may also be the last gas detector you will ever need to purchase.


Bob Pellissier
Founder of RKI Instruments

Our History

Celebrating over 80 years in the gas detection business, Riken has over 150,000 points of detection world wide in the semiconductor industry alone. RKI is the exclusive North American supplier of Riken products.


Riken develops first combustible gas monitors based on catalytic sensors, Interferometer.


Riken builds the first combination combustible and oxygen portable gas monitor with alarm, GX-3.


Riken introduces the world’s first 3 gas monitor (LEL, O2, CO) with alarm, Model 1641.


First pocket sized monitors from Riken, Models OX-80, CO-80, and HS-80


Riken introduces the world’s 3 gas, belt worn gas monitor, GX-82.


Riken introduces portable IR unit for CO2 monitoring, RI-411.


Riken offers a portable IR monitor for Freon detection, RI-413.


Riken presents world’s first 4 gas, belt worn portable monitor, GX-86.


Riken introduces the first super toxic gas monitor, SC-90.


RKI Instruments, Inc. becomes Riken Keiki’s North American partner with the introduction of is the GX-94, four gas, portable gas monitor with datalogging and auto calibration.


RKI and Riken together develop and introduce the first 6 gas portable monitor, the EAGLE.


GasWatch, the first wrist worn multi-gas monitor for O2, CO, or H2S.


Riken introduces the GD-K77D smart transmitter with greatly simplified calibration and maintenance.


RKI developed the Beacon 100 and 800 controllers. The Eclipse, NIC stand alone transmitter is also introduced with unique optical controls.


The worlds smallest 4 gas monitor, GX-2001.


Five sensor sample drawing personal monitor that measures % LEL and % volume methane, GX-2003.


RKI Instruments purchases a new building for the corporate headquarters located at 33248 Central Ave, Union City California


The smallest confined space 4 gas monitor, GX-2009


Six gas portable monitor with PID capability, EAGLE 2


Five gas sample draw with 3 operating modes and auto-ranging display of % LEL and % volume, GX-2012 multi gas monitor


Six gas sample draw with PID, IR, and super toxics, GX-6000 multi gas monitor


Leak checker for 40+ Gases fumigants, toxics, freons, and combustibles, SP-220


Benzene Specific PID available for GX-6000


MSHA GX-2009 available with NO2 Sensor

confined space monitors


GX-3R, world’s smallest 4-gas monitor / GX-3R Pro smallest 5-gas monitor with bluetooth connectivity for phone app, RK Link


The GasWatch 3 is the world’s smallest and lightest single-gas and dual-gas monitor. Weighing just 1.6 ounces, its compact form affords great comfort and flexibility in how you choose to wear it.


The 04 Series single gas monitor is designed to operate for many years with field replaceable sensors and filters.The 04 Series can be operated continuously for up to 9,000 hours on (2) AAA size alkaline batteries (depending on model). The 04 Series has 3 preset alarms that are user adjustable. Each version is also equipped with visual, audible, and vibration alarms as standard.


The GX-Force is RKI’s smallest personal 1-4 gas monitor with a strong internal sample pump capable of a 100’ sampling range. Weighing only 9.8 ounces, the GX-Force can monitor the standard confined space gases (LEL combustibles, Oxygen, Carbon Monoxide, and Hydrogen Sulfide).

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