Millimetres and micrometres
0.028 mm equals 28 micrometres (μm). The PET options of 0.029, 0.027 and 0.024 mm equal 29, 27 and 24 μm respectively. These are alternative units for the same thickness, not different product grades.
The same options apply to all six sizes
The customer can specify the listed material/thickness combinations for 16, 18, 32, 36, 38 and 40 inch number balloons. Do not assign a different mandatory thickness to a size without a product-specific reason.
The Nylon option confirmed here is 0.028 mm; the three PET options are not automatically Nylon options.
Availability versus recommendation
Although 0.024 mm PET is an available option, UNDALO advises against film below 0.027 mm. Keep the available-option list separate from the recommendation so that readers do not mistake availability for endorsement. This is UNDALO selection guidance, not a legal minimum thickness.
Thickness is not a stand-alone performance guarantee
Read thickness together with material, finished size and inflation guidance. Thickness alone does not establish that one construction outperforms another. The usual film-thickness tolerance is ±0.001 mm (±1 μm). Agree on the measurement instrument and measurement locations when setting thickness requirements.
Frequently asked questions
Which Nylon thickness is offered?
Nylon + PE composite film is offered at 0.028 mm for the number-balloon range.
Is 0.024 mm PET recommended?
No. It is available, but UNDALO does not recommend film below 0.027 mm.
Must a 40 inch balloon use 0.029 mm film?
No such requirement has been confirmed. All six sizes can use the listed Nylon or PET specifications selected by the customer.
What is the usual film-thickness tolerance?
±0.001 mm, equivalent to ±1 μm. This is a film-thickness tolerance, not a flat or inflated dimension tolerance.