Round Speaker, Diameter 36mm with 80mm wire and connector, 0.5W, 50 Ohms
Høyttaler – Wikipedia
I Key Buy 15-inch Iron Woofer Low Frequency Outdoor Broadcast Stage Bass Ktv Professional Speaker Diameter 383mm Magnetic 170mm - Speakers - AliExpress
UB+ Eupho E2+ 250mm Diameter Bluetooth Speaker - Amars Limited
Speaker driver beaming frequency formula | Audio Science Review (ASR) Forum