The Inova T4 is the first commercially available rechargeable lithium-ion LED duty light on the market. It is an exceptional light demonstrating excellent design and well executed use of some of the most cutting-edge illumination technology available.

The body of the Inova T4 is made of Type III anodized aluminum with square, flat checkering machined into the sides. Type III anodize is much harder and tougher than the Type II anodize found on common aluminum flashlights in department stores. The body finish is available only in black. The fit and finish are excellent. The bezel has a silver colored ring on the end with a recessed anti-reflective coated lens. Behind the lens is a special optical system called the TIROS, or Total Internal Reflection Optical System, designed to collect over 90% of the light produced by the Luxeon LED and project it forward. Inside the light is a regulation circuit designed to give constant output over the working lifespan of the rechargeable lithium-ion battery. The switch is a clickie type switch on the side. Included with the light is he charging base and adapters for AC and DC current. The AC adapter is designed so that the socket plug slides off and can be replaced with an assortment of adapters for use in many countries. The AC adapter has a switching power supply built in to detect the input voltage.

The bezel consists of a silver covered ring, two O-rings, and an anti-reflective coated glass lens. All of these parts are user-replaceable with an optional kit from Inova. Behind the lens is the TIROS light collection system which projects a very round beam with a dim sidespill. Inside is a Luxeon LED for light, which is essentially impervious to impact and never needs to be replaced.

Output is in the form of a gorgeous spot just like the other Inova T lights. Color temperature is high but there is no noticeable tinting in the beam.

   
Beam at one meter at target center and at target edge to show spillbeam.

Runtime Plot: The instructions state that you should get about 2 hours of light on a full 3 hour charge, that the output is regulated to maintain constant output over the usable energy-life of the cell, and that when the cell cannot produce the needed current the light shuts off completely with no dim mode (often called a "moon mode").

The runtime plot shows pretty much what the manufacturer describes! You actually get about 2 hr 30 minutes of regulated output before it plummets to darkness .

More information on runtime plots is available HERE.

The switch is a rectangular rubber covered clickie. Press in part way for momentary operation, press all the way in until it clicks for constant-on. The switch sits in a recessed cutout so that it is flush with the body tube. The switch gives positive audible and tactile feedback when activated. The switch can be locked out to prevent accidental activation by unscrewing the tailcap a little.

O-ring seals protect the body from the intrusion of water. I'd give it a "Splashable" rating. Pick it up, shake it off, and keep going.

Ergonomics: Very comfortable in the hand, good grip-ability, and not heavy at all. The switch is large and easy to operate.

Size compared to a common 2AA aluminum light

A single rechargeable lithium-ion cell is used to power the light, which is essentially state-of-the-art technology. Because the T4 uses this type of cell it can be recharged at anytime without the worry of a "memory effect". Two charging contacts are found on one side of the light. Orient these with the charging contacts in the charger base and press the light into the charger. A blue LED on the charger turns on when you have it right. When the LED turns off, you have a full charge. To use the light just grab the light near the tail and lift. The charger base uses two spring loaded rollers to hold the light, so it is easy to insert and remove the unit. Full recharge from a full discharge takes about 3 hours. The charger has a thermal detector and will not operate at temperatures above 115°F or below 20°F. Included with the light are AC and DC adapters and one charger base.

Optional accessories include replacement bezel ring/lens kit, assorted adapters for overseas use, 10' vehicle hardwire kit, replacement power cell, and replacement AC and DC adapters.

What I Liked: Water resistant, Tough/impact resistant, Regulated, Good battery life for a rechargeable, Bright, , Lightweight, Stands up

What I Didn't Like: Not a darn thing.

Other Things I Noticed: n/a

Conclusions: This light kicks butt! This is the first commercially available lithium-ion rechargeable Luxeon LED duty light on the market and everyone else is going to be scrambling to catch up. Great output, great beam, and very good runtime. Note that in terms of output and runtime, it's about the same as the Inova T3 and the XO3. It is not as bright as many rechargeable incandescent duty lights available currently, so be aware that it won't outshine a Stinger, Strion, or Magcharger. The lithium ion rechargeable system does make it inexpensive to use over a period of time relative to disposable cell lights. The charging system and the Li-Ion cell is state-of-the-art technology and appears to work extremely well.

Here's my recommendation: if the output level meets your criteria, get this light if you will use it frequently, get the T3 or XO3 if you will be using it infrequently or if you need to be able to carry replacement cells with you for on-the-fly battery changes. Either way you'll probably be very happy with your selection. All of the Inova T series of lights so far have received 5 Stars, and the T4 adds another 5 Star rating to their winning streak.

READER UPDATE Oct 13, 2005: The newest version of the Inova T4 has a charger that behaves a little different. While charging the light is a bright blue. It changes to a dimmer green when fully charged. The green light stays on as long as the light is in the charger (makes it very nice to find the light in the dark).

READER UPDATE September, 2006 from FFolkes: I just wanted to let you know that Inova has ceased production of the stainless steel bezel on their T4 light, and replaced it with black anodized aluminum. When I called they told me this was done to answer an increasing complaint from law enforcement professionals and tactical users.

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