Overall oven length ~13 in.

Central tube (mullite):
L = 12 in.
i.d. = 1.5 in.
o.d. flange ends 2.02 [2.0]
o.d. just inside flange 1.90 [1.875]
flange width: ~0.375 or 3/8 in

Wire
16 ga. (0.0508 in) 80/20 nichrome
approx 90-91 turns

Thermocouple thin tube (alumina):

~11 to 11.25 in. probably 11.
od 0.389 (0.375)
id 0.257 (0.250)