- Measured quantities
- VLT visible light transmission; UVR ultraviolet rejection; IRR infrared rejection
- Peak wavelengths
- Visible 530 nm; ultraviolet 365 nm; infrared 940 nm on LS160, LS162 and LS163, 1400 nm on the A versions
- Sample thickness
- Below 0.8 mm on the film models; 20 mm on LS101 and 47 mm on LS182
- Resolution
- 0.1%
- Display
- Backlit LCD showing the three readings together; a rotating large LCD on LS163 and LS163A
- Operation
- One key, which switches on and holds the reading; a sample placed in the slot is measured without further setting
- Power
- Four AAA alkaline cells, with automatic switch-off after three minutes
- Body
- 93 × 52 × 25 mm, about 70 g without cells
- Packing
- 150 × 80 × 50 mm case
A film is sold on three numbers - how much light it lets through, how much ultraviolet it blocks and how much infrared heat it rejects - and the buyer usually wants all three at the point of sale. This instrument is built for that moment: a sample goes in, three figures come out.
Product overview
A pocket body with a slot in the side, a display on the front and one key. The sample goes into the slot, the key is pressed, and the readings appear. There is no warm-up routine and no setting to choose before a measurement.
The range splits along two lines. The first is the slot: film only, or film and fitted glass. The second is the infrared wavelength: 940 nm for absorbing film, 1400 nm for metallised and reflective film.
Two wider-slot models sit at the end of the range. They take thick or laminated samples and report more quantities, including the thermal figures used in glazing specification.
How the meter reads a film
A source and a detector face each other across the slot. With no sample in place the detector sees the full source; with a sample in place it sees whatever the sample transmits. The transmitted fraction is the reading, and the rejection is its complement.
The measurement is made at fixed peaks rather than across a spectrum: a visible peak for light transmission, an ultraviolet peak for the UV figure and one of two infrared peaks for the heat figure. That is why the instrument is small and immediate, and also why its numbers are specific to those wavelengths rather than being an average over a band.
The choice of infrared peak is not a detail. An absorbing film works by taking energy into the film, and its performance is characterised at the shorter wavelength. A metallised film works by reflection, and its performance is characterised at the longer one. The same sample can look good on one instrument and ordinary on the other, and neither reading is wrong - they answer different questions.
How to select the right model
Start with what is being measured. Loose film, checked as stock or before fitting, goes in the film-only slot. A window that is already filmed, or a car side window being accepted at handover, needs the deeper slot.
Then the film type. Absorbing film takes the 940 nm models; metallised and reflective film takes the 1400 nm models. Where a shop handles both, the wavelength matters more than any other difference in the range, because it decides whether the reading corresponds to the film’s stated performance.
Then the display. The models with a rotating screen are for measurements taken at an awkward angle - inside a car, against a raked windscreen - where the body cannot be turned to face the operator.
Then the sample thickness. Film is thin; laminated glass, a glazing unit or a thick coated panel is not, and the wide-slot models exist for those.
Measurement limitations and selection considerations
The reading is only as good as the placement. The sample has to cover the aperture completely, sit flat against the slot and be clean; a fingerprint or a crease in the film reads as a loss of transmission, and an edge that does not cover the detector reads as a gain.
The numbers are not comparable across models without checking the label. Some report rejection, some report transmission, and one family adds the thermal quantities used in glazing specification. A 99.9% ultraviolet rejection and a 0.1% ultraviolet transmission are the same result described from opposite ends.
Scratched or hazy film reads low on visible transmission for a reason that has nothing to do with its specification. The instrument cannot tell an aged sample from a poor one, so a measurement on a used window describes the window as it is now, not the film as it was sold.
Finally, a three-peak reading is not a solar performance figure. It does not give the total solar energy rejected across the spectrum, and the thermal quantities that do - on the wide-slot model - come from a different calculation. Where a glazing specification has to be met, the figures have to come from the film supplier’s test report rather than from a hand-held check.
Every value below is taken from source documentation. Where a parameter is not stated in the available material it is marked as information required rather than estimated.
