Imperforate New Zealand Chalon heads may be altered to resemble more valuable roulettes. In this case the genuine is rouletted 7, but the 2p blue also exists serrate perf (a form of rouletting) 16 and 18, pin perf 10, "H" roulette 16, "Y" roulette 18, oblique roulette 13, square roulette 14 and serrate perf 13.