Espressif Systems Co LTD (Shagnhai) manufacturers WiFi and Bluetooth modules often with the prefix “ESP####”. Espressif has many FCC approved devices listed here. Their extensive mac address list includes many vendor prefixes as they produce a number of modules that are included in consumer devices such as WiFi and Bluetooth LED bulbs, SimpliSafe products, as well as automotive data loggers (IOSiX ELD). They also make a number of modules commonly included in DIY electronics projects.
Within the networking world, their brand is often shortened to Espressi. If you are able to identify an Espressi device on your network, please share in the comments the brand/model of your device as many users are often confused what type of Espressi device they are having on their network.