If you integrate, or are planning to integrate a Vera system with HomeKit using the excellent Homebridge-Vera integration then you may well want to ensure that things like your relays appear as an appropriate device type in HomeKit.
By default when adding relays to Vera they will appear as lights, this is determined by their category and subcategory. Most relays will be entered as category three (3) which is switches, and likely subcategory three (3) which is specifically in-wall switches. With this default setting however when displayed in HomeKit they will display as a light switch, not ideal if you in fact have say an extractor fan attached.
This is thankfully easy to fix, if you go to the device in Vera and then select "Advanced" you will be able to set the device parameters, simply change the sub-category to be sub-category four (4) instead. When the sub-category is four (4) then the VeraLink script will present it to HomeKit as an appliance type switch that you can select what device it actually is.