then a plug with lm greater than 50 th may be preferably selected to repair the flat tire lm may be greater than 50 th 60 th 70 th 80 th or 90 th as shown in fig8 when lm is greater than 50 th position pm will pass the half thickness line of the tire th 2 as a result the u201c force down u201d from the elastic tire material imposed on body 60 which pushes the plug 100 inwardly will be greater than the u201c force up u201d from the elastic tire material imposed on body 60 which pushes the plug 100 outwardly therefore plug 100 is sturdily stabilized and maintained inside the tire material as shown in fig9 the present invention also provides a kit like a tool box 200 comprising a plurality of the plugs 100 a b c d e f g h i and etc at least two of the plugs selected from 100 a b c d e f g h i have different dm values and or different lm values the kit may further includes a container 201 containing a curable coating material 70 and a tool 202 for driving the plug 100 into the hole 58 kit 200 occupies a small space and can be quickly applied without the use of special tools in exposed and otherwise.