When deciding on the best fully insulated female spade connector, you should take into account the wire size (mm or AWG) and the tab size that it will be connected. The width of the receptacle should match the width in the tab, as well as the thickness of the tabs can vary greatly. Common tab sizes include .110 (2.8mm), .187 (4.8mm), .205 (5.2mm), .250 (6.3mm), and .375 (9.5mm). Proper selection ensures a safe and secure and reliable electrical connection.