Based on this product's specifications, here are some alternatives and similar models
Portable Fish Finder deeper START — wireless Wi‑Fi sonar, 120 kHz, max depth 50 m, 40° beam, 850 mAh LiPo battery
Summary description:
deeper START is a portable wireless fish finder with a 120 kHz sonar and 40° detection angle, designed for depths from 0.5 to 50 m. Made of ABS and fully waterproof, it connects via 802.11 b/g Wi‑Fi to mobile devices. Powered by an 850 mAh LiPo battery (≈6 h runtime, 2.5 h charge) and charged via micro‑USB. Suitable for shore or boat use to locate fish and map underwater structure.