With the kit of studio strobes that I bought, came a standard reflector for each head. Some strobes I have seen come without these, or have some built into the flash head. I like these as they are, with the universal Bowens mount. So I can take them off when using a soft box with my strobe, or any other light modifier. Also, they have a strap cut out in the reflector that can be opened so when mounting an umbrella, the rod of the umbrella will go through the hole in the reflector and into the dedicated hole on the bracket where the strobe head is mounted to the stand.
These reflectors give a strong and hard light. They are silver coated inside, looking like small droplets.