RETEVIS RT622 walkie talkie 2 pcs walkie talkie PMR 446 walkie talkie for hunting walkie talkie portable communication equipment walkie talkie for hunting Mini two way radio with Russian voice prompt

Price from 22,18 $

Needed for fishing. I never bought it before. Question: why reflash, and how to do it?
Brand name: RETEVIS
Battery capacity (mAh): 1000
Origin: China
Display Availability: No
Waterproof/Water Resistant: No
Walkie Talkie Type: Portable
Maximum range: 1.5km-3km
Output power (W): 0.5W-3W
Certification: European Certificate of Conformity
Certification: FCC
Certification: RoHS
Model Number: PMR:RT622 or FRS:RT22
Frequency response: PMR:446MHz or FRS:462MHz
Dimensions: 5.32x2.16x0.84inch(13.5x5.5x2.14cm)
Number of channels in memory: 16
Output power: PMR:0.5W or FRS:<=2W
Squelch level: 0-9
VOX levels: 1-9
Weight: 3.99oz(113g)/pc
Antenna type: Integrated antenna
MIC/Speaker Port type: Compatible with 2 pin K plug accessories
Usable programming cable: C9018A/C9055A
Certificate: CE/FCC/IC
is_Customized: Yes
Support Dropshipping: Yes
Battery Life: Working time:8-12 hours; Charging Time:3-4 hours