It's the ESP32 (WiFi and BLE module) but what's real nice about these is the fact that they also have an IPEX connector should you want to put down an antenna with better gain.
Chipset: ESP32-D0WDQ6 (Dual core processor)
Datasheet: Click for datasheet
Processor: Xtensa® 32-bit LX6 Dual-core processor, up to 600 DMIPS.
448 KByte ROM
520 KByte SRAM
16 KByte SRAM in RTC.