Tranmere Rovers have signed defenders Calum Woods and Sid Nelson and wingers Kieron Morris and Corey Blackett-Taylor.
Woods, 32, who was released by Bradford City in May, joins on a one-year deal.
Centre-back Nelson, 23, has agreed a two-year contract after being on loan at Tranmere from Millwall in the second half of last season.
Also making a permanent switch on a two-year deal are Morris, 25, and Blackett-Taylor, 21.
Morris was previously on loan from Walsall, while Blackett-Taylor came through the youth ranks at Aston Villa.
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