Mirror Class rules allow any number of spinnaker pole systems. When spinnakers were introduced in the 1960's Mirrors had "end to end" systems with, ideally, rope uphaul and elasticated downhaul. In the mid to late 80's the "Sidey Rigid Pole" system was a popular alternative method of fixing the pole height with some. Around the mid 1990's the "Flyaway" pole system was introduced by Stephen Heppell from Brightlingsea. This was to make it easier for his daughter Juliette's crew, Hannah Stodel, to fly the spinnaker (Hannah has a disability). Since then the flyaway gained popularity for those with small crews or sailing single handed. The "end to end" system remains popular with bigger stronger crews and is the system used by sailors in the RYA Mirror National Junior Squad. It is also the system used on the RYA pathway class the International 420 and the Olympic class the International 470.
Below are links to descriptions of the most common spinnaker pole systems. Within each system there are often further options for fittings or other equipment
Flyaway pole with deployment line lead back to helm (2003 article by Stephen Heppell)
Flyaway pole - additional information
End to end pole with conventional rope uphaul & downhaul
End to end with 'Sidley Rigid Pole' support