what is different flange band leakage guards and flange band protection

1.flange band protectors

flange band protectors have injection fitting,and Safety relief valve,

Line:Neoprene/EPDM

band tightly:worm gear clamp

only uesed for anti corrosion flange injoint

Flange Protector Bands - Flange Studs Protector,Flange Nuts Caps,Flange Bolts Protectors (nutcaps.net)

2. flange band leakage guards

flange leakage guards 

Line:PTFE

band tightly:Bolt and nut 

with drain system

most used flange leakage protection 

Band type flange cover - Sealing and leakage drainage system for flange leakage and sprayout (leakcover.com)