mwave offers the Premiertek 802.11n 9dBi Screw-On Antenna, model no. ANT-9dBi, bundled with a $1 mwave credit for $5.49. With free shipping, that’s tied with our May mention and the lowest total price we could find by $9. This antenna purportedly increases wireless signal strength from 2dBi to 9dBi. It screws directly onto a router or network adapter.