I'm currently sending these by 1st Class post due to delays in the Royal Mail postal system.

Pack of 2.  3.5mm 3 Pin TRS Plug to Standard 5 Pin MIDI Socket Adapter Lead - Type A

There are several different types of these adapters, when companies started using 3.5mm connectors for MIDI there was no standard so not all companies use the same wiring.

An example list of equipment that uses this Type A connector:

Akai - MPC Studio, MPC Touch
Korg - Electribe 2, SQ1, NTS-1 (Check the manual for the MIDI channel settings on the NTS1 as they are unusual, eg Channel 1 does not appear as 1 on the display)
Line 6 - MIDI Mobilizer, MIDI Mobilizer II
littleBits - w5 MIDI Module
Make Noise - 0 Coast
IK Multimedia - iRig MIDI, iRig Pro, iRig Pro DUO
Boss (Roland) - Loopers - RC 10 and RC500

Wiring inside the cable is:
Tip - Pin 5
Ring - Pin 4
Sleeve - Pin 2

Length of cable is 15cm

I am a UK seller and items are posted from the UK.