Newbie question- siren low battery

[The Mantis]

I‘m attaching a couple of shots of my control panel which was installed a few years back by a small local business which now seems impossible to contact.
I imagine this box must be pretty generic but I haven’t been able to see any branding. I’ve previously been able to replace the batteries in the 3 remote sensors myself but the other night I got the alert that the wireless siren battery was low.
I haven’t been able to find anything similar on YouTube.
I had a tentative go at it as there seem to be two slots on the top to get into the casing but I’m a bit apprehensive about it. I’m assuming that there are users out there who will recognise the box?Thanks in advance
John

 

[DIYSOS2018]

That’s a Pyronix enforcer so it’s likely you’ll have a wireless deltabell on the outside wall

Flip down catch in the centre bottom to uncover a screw, unscrew, flip open lid to get into the insides and it’s likely you’ll have 2 square style batteries that plug in independently. Close lid, screw back in, cover back over screw job done.

Hint - take up ear defenders

 

[The Mantis]

That’s a Pyronix enforcer so it’s likely you’ll have a wireless deltabell on the outside wall

Flip down catch in the centre bottom to uncover a screw, unscrew, flip open lid to get into the insides and it’s likely you’ll have 2 square style batteries that plug in independently. Close lid, screw back in, cover back over screw job done.

Hint - take up ear defenders

Thanks for the quick reply, it’s dark now so I’ll have a look tomorrow. What I assume you mean by the deltabell is out the back on the far end of the garage. I’ve always assumed it was a dummy and we’ve never heard it in the house over all the other din.