yes, they are helper springs. the guys in the frontier community raved about them all the time too. they were actually installing them upside down, and the front side of the leaf. they said it would sort of act like a traction bar.... i never tried them, even though it was cheep. i figured i could either try this mod that "supposedly" works, or buy myself a bottle of whiskey. i went for the whiskey

these ones that the OP is talking about look a little more spendy....

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2008 DC, 4x4, TRD 5.7L
2.4 Ready-Lift, 305/55/20 Mickey Thompson Baja ATZ's on 20'' Ultra Goliath's and 285/65/18 BFG AT's on stock TRD rims, grille surround, door handles, and tailgate handle painted to match body, black headlight mod, OEM fender flares, Lorado tonneau cover, N-Fab nerf bars, 6000K HID lows and highs, 3000K ebay special fogs, Tekonsha P3 brake controller, Firestone airbags, LED tail lights, LED 3rd brake light, Pioneer AVH-P4100DVD head unit, Kicker KX600.1, Rockford 450.4, Kicker Resolution 6.5'' components front and rear, Kicker 12'' L7

1995 Dodge Neon puddle jumper

2009 Polaris Sportsman 550 EFI Power Steering

2005 yamaha raptor 70+ hp!