Editing ITT ETL18 (section)

==Description==
The name "ETL18" is taken from the branding on the top of the switch. A search for ETL18 at Oxygen Electronics (as of November 2016) returns two results: ITT ETL18 (depicted per other discovered ETL18 switches) and ITT ETL18H1X1GC.<ref name="O2" /> The latter may refer to a specific part in series ETL18, which would make sense as more than one product in the range is likely.

The switch is relatively large: the ridge that sits above the plate is 18 mm square, while the body is 16.3 mm square. Shell height is 13.6 mm, and the top of the mounting plate comes 11.6 mm above the top of the PCB. These non-[[DIN-compliant]] dimensions are curious for a German-made switch patented only a year before widespread adoption of DIN-compliant dimensions in 1983.

The keycap mount is proprietary cruciform; the switches do accept SMK keycaps made for [[SMK J-M0404 series]] switches. Cherry MX keycaps do not fit. The cross arms are the correct width to accept Mitsumi Commodore 64 keycap, but the slot widths within the keycap allow it to tilt on the keystem.

The switch features [[sealed terminals]] (with grey sealant instead of the typical red) and two recesses underneath to allow diodes to be placed below the switch.

===Internals===
The ITT switches are different from other internal spring-based key switches in that the spring is horizontally mounted through the key stem as depicted below. The dual metal contact fins appear to be for a dual pole switch but they connect to single contacts at each end of the switch. The tactile feel is provided by the internal [[Horizontal spring]].

Testing with a multimeter demonstrates that the spring and contact arrangement does not provide [[hysteresis]].