How to cut space for keyhole hanger without a router?

Can we use hanging wire with keyhole hangers? Hopefully this is an appropriate question for this group, but we have a few mirrors that need

Each test slug should only take about 10 minutes to print Tags wall frame picture hanger mount + More Model origin The author hasn't provided the model

keyhole slot hanger Keyhole Hanging Kit takes the pain out of hanging products with keyhole slots Hello Sandra, we are sorry to hear the Keyhole Hangers did not work for you

keyhole slot plug key- hole slot , and supported by two columns and flanged top or loop , they hangers They can be adjusted to the thickness of floor slabs No