The WEISHI Twist-To-Open (Chinese replica Gillette's - I believe) use a Cuprum Alloy (a form of Bronze - good solid weight) with a Noble Metal Electrolosis for the 9306 series and an aluminium alloy for the 2003M razors - very light.
In fact I used a 9306 (mine is in matt chrome) this morning with a Wilkins Sword (UK factory) this morning and was plesantly suprised again it is truely an extreemly gentle razor