Selector button mounts instead of standard lever at the left side of carbine frame. Standard lever sometimes interfere with sling, catch on clothes and do not provide required functions.
With button you will get sleek round shape much easier to use.
Selector button installation manual for Vepr molot 205
2. Hold receiver up
3. Take operating spring from slot
4. Remove operating spring
5. Lift right selector lever up
6. Up to vertical position
7. Disconnect left lever from right one
8. Put plug into right lever slot
9. Push to the stop and lower right lever to the place. Assemble in reverse order.