Particular aspects provide devices and methods for adjustably and reversibly engaging a line (e.g., fishing lines, ropes, string, cable, wire, cords) at an engagement position and/or for demarcating positions/spans along a line. The inventive line-stop members are reversibly disengagable, and thereby slidably adjustable and positionable along a line, and can be used to define a user-selectable range or span. Particular embodiments comprise: an elongated line-clamping member having at least one pair of line-clamping arms and having a longitudinal axial bore suitable to allow slidable passage of a line therethrough and a cylindrical engagement collar having a collar channel therethrough and slidably positionable along the line-clamping member, and suitable and positionable to reversibly hold the line-clamping member in a line-clamping/engagement position, and suitable and positionable to reversibly disengage the line-clamping member from the line-clamping position to reversibly disengage a line. Preferred line-stop embodiments comprise an accessory attachment member or collar.
