This round post bracket is an optional bracket which can be used when installing the E8 or TMT swing kits and you have a round post that your gate swings/hinged from. 

The standard post bracket supplied in the kit is a 100mm x 90mm square flat bracket. 

If you do have a round post and it is large enough to notch a flat spot into, then you can use the standard bracket supplied. 

However, if you think notching out the post may weaken it, then definitely consider this round post bracket.