League One outfit Tranmere Rovers have completed the signing of defender Mark McChrystal on a six-month contract.
The 26-year old joins from his hometown club Derry City where he has spent the last three seasons.
McChrystal began his career at Wolves, has also spent time at Partick Thistle and spent two weeks on trial at Prenton Park earlier this season.
Rovers manager Les Parry said: "We brought Mark in the two weeks at the end of October when he trained with us and played in a couple of friendlies.
"He is an experienced player who was with Wolves for a number of years. He is a leader, he talks and is the type of player other players will look up to."
Rovers have also agreed a deal to keep on-loan West Brom striker Lateef Elford-Alliyu for another month.