Invisible Vs Conventional Window Grille Along Corridor Unit

[mummychua 4]

Anyone installed invisible grille on their corridor unit? Understand that the invisible grille comes with alarm system but is it of any use? if a burglar tried to break into your unit, a normal aluminium type of grille can too be cut open right? Anyone have problem when your grille can't be slide open?

[tessina 9]

Strongly suggest to stick to lock-able sliding alum or wrought iron grilles (or even fixed iron grilles) for the corridor windows.