The In-Check Flo-Tone® is an approved dual spacer and pressurised metered dose inhaler (pMDI) patient training device that indicates the optimal pMDI actuation point during the inhalation manoeuvre. The device fits many but not all pMDI actuators. A development programme has been undertaken to tailor the existing device to a range of pMDIs that vary in mouthpiece configuration and actuator resistance. In this study Flutiform® Landmark® pMDI (FL, 5g formoterol fumarate/125g fluticasone propionate, Napp Laboratories) was tested alone or in combination with machined or moulded adaptors paired with either standard Flo-Tone or Flo-Tone development devices: anti-static plastic, a short device, and a short, flared mouthpiece single unit prototype (the Flo-ToneCR). Aerosol particle size distribution and dose characteristics were derived from Next Generation Impactor experiments conducted at 30 L/min. In all assessments, formoterol and fluticasone data trends were the same. Fine particle fraction (FPF) and fine particle dose (FPD) data were comparable between FL alone and the moulded adaptor plus short Flo-Tone device combinations. The formoterol FPF (%) and FPD (g) values were 50.432.14 and 2.190.14 for FL; 50.751.04 and 2.130.06 for the short Flo-Tone; and 50.223.10 and 2.430.03 for Flo-ToneCR. Preliminary data with the Flo-ToneCR to determine reed whistle vibration and detectable whistle flow rates, across a range of commonly used pMDIs, suggest that the actuation indicator sounded at 20-25 L/min. This programme has shown that it is possible to tailor an existing audible training aid to a broader range of pMDIs and actuator designs without drug delivery compromise.