Topper Mast Collar (post March 2014) Complete with a 4mm rivet needed for the job. Note, will only work with the new gooseneck too. Image below showing the location of the D11 Collar (the top fitting) and its orientation. View the video installation guide How old is my Topper? Below is a small table extract of Topper Sail Numbers versus build date/year for 2013-2015 Build Date Sail Number Jan-13 47413 - 47418 Feb-13 47419 - 47426 Mar-13 47427 - 47435 Apr-13 47436 - 47450 May-13 47451 - 47460 Jun-13 47461 - 47483 Jul-13 47484 - 47517 Aug-13 47518 - 47531 Sep-13 47532 - 47533 Oct-13 47534 - 47541 Nov-13 47542 - 47553 Dec-13 47554 - 47562 Jan-14 No data Jan-15 47666-47693 Feb-15 47694-47721 Mar-15 47722-47749 Apr-15 47750-47760 May-15 47761-47775 Jun-15 47776-47804 Jul-15 47805-45821 Aug-15 47822-47834 Sep-15 47835-47859 Oct-15 47860-47874 Nov-15 47875-47902 Dec-15 47903-47927