Roof flashing

A roof flashing comprising:

• a bottom half having a first plate extending in a first plane and a first neck portion projecting away from said first plate and said first plane, said first neck portion being arcuate and centered on a first axis that intersects said first plane at an acute angle, said first neck portion defining a first portion of an aperture configured to encircle and seal against a post projecting away from a roof;
• a top half having a second plate and a second neck portion projecting away from said second plate, said second neck portion being arcuate and centered on a second axis that intersects said second plate at an acute angle, said second neck portion defining a second portion of said aperture;
• and
• at least part of said first neck portion is slidably receivable in said second neck portion, said first neck portion and said second neck portion defining a neck of said roof flashing when said bottom half and said top half are engaged with one another;
• wherein said first plate extends a length between an upper edge and lower edge, said upper edge positioned closer to said first portion of said aperture than said lower edge, further wherein at least part of a perimeter of said first neck portion about said first axis is received in and overlapped by said second neck portion, said at least part of said perimeter defined beyond said upper edge and not along said length;
• and
• wherein said second plate extends a length between an upper edge and lower edge, said lower edge of said second plate positioned closer to said second portion of said aperture than said upper edge, further wherein second neck portion does not extend past lower edge of said second plate and extends along said length of said second plate.