The Brainwavz S1 IEM is on sale now at $29.50 with free delivery. From what I can tell, the S1 uses 10mm dynamic drivers. 16 ohm impedance means you can easily drive them using your iPhone, Androids, etc…
Specifications:
Transducers/Drivers: 10mm
Rated Impedance: 16ohms
Sensitivity: 93dB at 1mW
Frequency range: 20Hz ~ 20KHz
Maximum input power: 2mW
Cable length: 1.3m, Y cord, OFC Copper, flat cable.
Plug: 3.5mm gold plated, 45 degree.
12 month warranty..
*Included Accessories:
1 pair x Comply foam tip T-400
2 pairs x Silicone tips (S)
2 pairs x Silicone tips (M)
2 pairs x Silicone tips (L)
1 pair x Dual Layer Silicone Eartips
1 pair x Three Layer Silicone Eartips
1 x Earphone carrying hard case
1 x Instruction manual & Warranty Card
Reviews:
Brainwavz S1: Fortune Favors The Bold! (http://www.head-fi.org/t/681503/brainwavz-s1-fortune-favors-…)
Brainwavz S1 Review by Bowei006 (http://www.head-fi.org/t/680493/brainwavz-s1-review)
Review: Brainwavz S1 (http://www.head-fi.org/t/684762/review-brainwavz-s1)
Brainwavz S1: Brainwavz Bassheads (http://www.head-fi.org/products/brainwavz-s1/reviews/9816)
Brainwavz S1 Review @ Stozz (http://www.stozzaudio.com/latest/2014/8/21/brainwaz-s1-revie…)
how do this compare to meelectronc m-duo or a151p