I have noticed that a white 'mark' appears on the airspeed strip along with the V speeds. I checked the manual but could not find a reference to it. Any clues would help.Thanks in advance.

>I have noticed that a white 'mark' appears on the airspeed>strip along with the V speeds. I checked the manual but could>not find a reference to it. Any clues would help.>>Thanks in advance.That is Vref plus 15 knots used in approach, before slowing to Vref + 5

Reference: B737-700 FOMThat would be the (white) V2+15 Bug.Displayed for takeoff.Removed when either of the following occurs:-at the first flap retraction-when Vref is entered in the CDUThis airspeed bug is automatically set 15 knots above command V2 speed. V2+15 provides 40 degrees bank capability (25 + 15 degree overshoot) for all takeoff flaps.A Vref+15 (white) bug is also displayed upon entry of the landing flaps speed in the FMC.Floyd

Many thanks chaps, I had a feeling it was something along those lines.