A rotation angle indicating retainer assembly for use with and/or integrated with a hydraulically driven device for tightening and loosening a threaded fastener, the rotation angle indicating retainer assembly including: a retainer cap assembly having a substantially hollow cylindrical shape with an upper hollow portion , a lower hollow portion , a hollow disc , a ring having polygonal connection formations and a ball bearing assembly ; a plunger assembly having substantially cylindrical shape with a connection portion , a depression portion , a compression spring and a lower retaining ring; a rotation angle scale assembly having a substantially hollow cylindrical shape with an upper hollow disc with an arrow indicator and a lower portion having polygonal formations ; and a rotation angle indicator assembly having a substantially hollow cylindrical shape with an upper rotation angle dial , a lower portion having a rotation angle scale , an upper retaining ring , a wave spring and a friction ring , wherein when installed on the device : the plunger/button assembly is formed within the retainer cap assembly ; the retainer cap assembly is: formed between the rotation angle indicator assembly and the rotation angle scale assembly ; ttached nonrotatably relative to a square drive shaft torque output assembly of the device ; the rotation angle indicator assembly is formed over the retainer cap assembly ; the rotation angle scale assembly is: formed under the retainer cap assembly ; and attached nonrotatably relative to a driving portion of a housing of the device . a retainer cap assembly having a substantially hollow cylindrical shape with an upper hollow portion , a lower hollow portion , a hollow disc , a ring having polygonal connection formations and a ball bearing assembly ; a plunger assembly having substantially cylindrical shape with a connection portion , a depression portion , a compression spring and a lower retaining ring; a rotation angle scale assembly having a substantially hollow cylindrical shape with an upper hollow disc with an arrow indicator and a lower portion having polygonal formations ; and a rotation angle indicator assembly having a substantially hollow cylindrical shape with an upper rotation angle dial , a lower portion having a rotation angle scale , an upper retaining ring , a wave spring and a friction ring , wherein when installed on the device : the plunger/button assembly is formed within the retainer cap assembly ; the retainer cap assembly is: formed between the rotation angle indicator assembly and the rotation angle scale assembly ; ttached nonrotatably relative to a square drive shaft torque output assembly of the device ; the rotation angle indicator assembly is formed over the retainer cap assembly ; the rotation angle scale assembly is: formed under the retainer cap assembly ; and attached nonrotatably relative to a driving portion of a housing of the device . formed between the rotation angle indicator assembly and the rotation angle scale assembly ; ttached nonrotatably relative to a square drive shaft torque output assembly of the device ; the rotation angle indicator assembly is formed over the retainer cap assembly ; the rotation angle scale assembly is: formed under the retainer cap assembly ; and attached nonrotatably relative to a driving portion of a housing of the device . formed under the retainer cap assembly ; and attached nonrotatably relative to a driving portion of a housing of the device . <EOS>