Hygrometers and temperature guns are both useful tools when performing routine husbandry maintenance. They are both devices that help in calibrating the environmental conditions within your enclosure to ensure you snake is healthy and comfortable.
Hygrometers
One major aspect of husbandry is humidity. While many species do not require much maintenance with it, some species such as the Ball Python require some level of regulation for humidity to assure their snake is happy and healthy. For new keepers, managing humidity can be a big challenge; but with the use of a hygrometer, this challenge becomes a little easier.
Hygrometers are devices that simply measure atmospheric moisture, or humidity. Some hygrometers use wired probes to detect humidity, while others are stand-alone and are to be placed directly in the enclosure itself. Which design you choose is entirely up to you and what you think would be best for your setup; although the less wires in the enclosure, the better. That said, do not confuse a hygrometer with a hydrometer. Hydrometers are entirely different devices that will not help in managing the humidity within your enclosure.
When choosing a brand and model of hygrometer, it is suggested that you look for one that is not only accurate and reliable, but durable, as well. Lower quality hygrometers tend to malfunction within just a few weeks due to lack of durability. As with your thermometer, it is highly recommended you purchase a digital hygrometer over an analog one. Analog hygrometers are not only inaccurate, but their method of placement often includes sticking an adhesive backing to the enclosure, which puts your snake at risk. There have been many reports of analog gauges falling from their position and sticking to snakes, often tearing their scales and sensitive skin from their bodies upon removal. Therefore, it is better to avoid all the hazards that come with analog gauges and go for high quality digital ones instead. Reliable brands of hygrometers include ThermoPro and Govee, both of which have models that serve as a thermometer as well. Some models are even compatible with a mobile device to monitor your husbandry from your phone.
Luckily, setting up your hygrometer is easy. If you are using a standalone hygrometer (without a probe), simply place it somewhere safe within the enclosure where it will not be disturbed. One method of doing so is to secure a plastic hook to the inside of the enclosure with silicone to hang the hygrometer on. If you are using a hygrometer with a probe, secure it somewhere in the enclosure where it will not be disturbed by your snake. If your probe gets wet or damaged, it will not provide an accurate reading, so securing it in a safe location is important.
Temperature Guns
While commonly overlooked, the temperature gun is an incredibly useful tool to have on hand when performing routine husbandry management. Temperature guns are thermometers that measure the temperature of a given source from a distance, which is indicated by the user through a laser-pointer installed into the device.
In regards to reptile husbandry, temperature guns are most often used to check the temperature of a specific area within the enclosure, such as the hot spot. Many keepers who use under-tank heaters utilize temperature guns to accurately calibrate their thermostat to compensate for heat transfer. They can also be used to measure the surface temperature of water, and just about anything else. That said, temperature guns are meant to measure the temperature of the immediate radius (as indicated by the laser) and should not be used to measure ambient temperature, which should measure the surrounding radius. There are a few different brands of temperature guns, but the higher the quality, the more accurate it will be and the longer it will last. Brands such as Etekcity and Hotodeal offer high-quality temperature guns that are excellent for reptile keepers.
In conclusion, hygrometers and temperature guns are useful devices that help the keeper calibrate and manage their husbandry. They are especially crucial for new keepers that aren't familiar with how to adjust and maintain the environmental conditions within the enclosure, so be sure to add them to your checklist!