GLASSESSENTIAL® Folding Window Grilles are designed to provide elegant look, strong security barrier with ease of operation.
Decorative Window Bar Security - Example 1
Decorative Window Bars - the next step. Just be sure they have a quick release, or you'll have to remove them when you sell. Fire code and all. :)
Window Security Bars - Tudor diamonds - custom sizes look like they're available in the $100+ range
Check out this affordable home security idea to protect your windows from break in.
Window Security Bar - Found this awesome Product at qcidirect.com
Lexan-ClearBars - Transparent Burglar Bars
Window Security Guard, Adjustable, 3-Bar: Model# 1133 | True Value
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Hinged Removable Bar - Hinged - basement window bar 1 - Canada Window and Door Security