This is a red insulated binding post. These binding posts *do* accept banana plugs, and are a great way to connect single-wire leads. The colored cap screw
Hackers in Residence - Cosmic Ray Detector - SparkFun Learn
Binding Post - Red (PRT-09739) - Sparkfun - Core Electronics Forum
PRT-09915 SparkFun PRT-09915 Stærð laus frá Infinity
Description Features These are various leaded cables for attaching to multimeters, power supplies, oscilloscopes, function generators, etc. Cables
Banana to IC Hook Cables
Pomona 3760-2 Binding Post, TIN PLT. (RED): : Industrial
PRT-11363 SparkFun
Catalog Sparkfun APR 2013, PDF, Switch
PRT-09835 SparkFun PRT-09835 Stærð laus frá Infinity
Banana to Test Probe Cables - CAB-00505 - SparkFun Electronics
Binding Post - Red - PRT-09739 - SparkFun Electronics