and the gasket 22 in addition referring concurrently to fig1 and 4 the gasket 22 encompasses pairs of hooks 34 protruding from the exterior edges 46 and 47 of the flexible portion 24 preferably in juxtaposition with the u shaped edges 48 thereon the hooks 34 symmetrically located on opposing sides of the u shaped edges 48 are means of attachment and alignment for the gasket 22 onto the arcuate base plate 18 of the sector 10 the hooks 34 oppose the tabs 32 on the flexible portion 24 but essentially have the same function which consists of attaching the gasket 22 to the arcuate base plate 18 of the sector 10 advantageously the hooks 34 ensure that the u shaped edges 48 are properly aligned with and centered on the bolt holes 50 fig4 on the arcuate base plate 18 in another embodiment of the present invention the gasket 22 is provided with crenellated portions 52 which are best illustrated in fig1 more distinctively the whole crenellated portion 52 can be described as having two merlons 54 and one crenel 56 and is shown as integrally moulded within the flexible portion 24 and integrally connected to the aforementioned hooks 34 it is pointed out that an alternative configuration can also be effectively employed whereby the crenellated portions 52 are integrally connected to the aforesaid bands 38 and hooks 34 as shown in fig5 the integrally moulded piece 58 is a combination of the crenellated portions 52 connected to the hooks 34 and to the bands 38 which are integrally joined to the tabs 32 preferably the crenellated portions 52 are at right angles with the bands 38 referring concurrently to fig1 4 and 5 it is preferred that.