Where to buy overflow kit

I wana drill my 40 breeder and want a kit and how to see if it tempared glass problem is I already painted the back
Ik I saw a tag that said assembled by name and then it has h112a under that

 

Can any one help.
I wana know if the number tells me
And what kit ppl suggest for drill an over flow kit
And for gph what should I aim for something around 400+ on gph was thinking more of 500-1000 gph for overflow

 

Ok well I think I found the answer, im sure its not tempered glass, I will look for a overflow kit myself

 

There are multiple places to check,
Have you tried the main sites like
Bulk reef suppy
Marine depot
Salty supply
Also I know Amazon has them

 

polarized glasses to figure out if you have tempered glass of not and here is what i use.

TUNZE GmbH High-Tech Aquarium Technology: Catalog

 

Problem is back of tank is already painted this making the polarized glass trick hard

 

Sides?

 

No they arnt, but I dont have any polarized sun glasses either.

 

Well, even if the back is painted you can check the other sides. If none of them are tempered then your good. Sometimes they temper the bottom pain and not the sides. The tag with the number you found I believe is a way to track who specifically assembled the tank at the factory. That way they can track them down if there are build issues.

 

Most likely it's not tempered. Glass holes.com make excellent overflows.

Aquarium overflow box 700gph